project impact curr 231 curriculum and instruction in math session 7 chapters 10 & 11

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Project Impact CURR 231 Curriculum and Instruction in Math Session 7 Chapters 10 & 11

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Project Impact CURR 231Curriculum and Instruction in Math

Session 7

Chapters 10 & 11

Outcomes Number Talk – Text – Teaching Math Ch. 10 & 11 Activity - Trace Essential Standard through

text Video – Number Talk Make and Take – Tessellations, Pattern

Blocks Game time – student led

Number Talk

46 + 28 = 27 + 50 – p

What is the value of p?

Justify your solutions.

Chapter 10: Measurement:Assigning a Number to a Quantity

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Presentation 10a Teaching Length

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

When children are learning about length, several things should be accomplished. It is recommendedthat instruction be structured so that they will learn those things in the following order.

• understand what length is

• understand the concept of unit of length

• become familiar with standard units of length

• develop the ability to estimate lengths

The children must

• develop proficiency using length-measurement tools

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We will now examine each of those things in depth.

First, the children must understand what length is.

That understanding is usually learned most efficiently by making a variety of comparisons.

The comparison examples should include other attributes that might possibly be confused with length.

Such examples allow the child to realize that each of those other attributes is not length.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We might begin with a simple example like this one.

Which of these objects is longer?

This one is longer.

The one on top is longer.

But the child might not understand what is meant by “longer.”

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We must include examples that clarify that the one on top is not always the longer object.

Which of these objects is longer?

This one is longer.

The orange one is longer.

But the child still might not understand what is meant by “longer.”

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We must include examples that clarify that the orange one is not always the longer object.

Which of these objects is longer?

This one is longer.

The one that goes straight across from left to right is longer.

But the child still might not understand what is meant by “longer.”

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We must include examples that clarify that position does not determine which is the longer object.

This one is longer.

The fat one is longer.

But the child still might not understand what is meant by “longer.”

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We must include examples that clarify that “fatness” does not determine which is the longer object.

This one is longer.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

So, we see that by increasing the variety in our examples, we are able to clarify the attribute that we are measuring

Next, the children must understand the concept of unit of length.

A unit of length is a piece of length.

Units of length are movable.

Units of length are countable.

—length.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Suppose we place two objects on opposite sides of the room and ask the children which is longer , but we tellthem that they cannot move the objects to check.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We can cut a piece of string so it is as long as one object

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We can cut a piece of string so it is as long as one object, then we move the string and compare itslength with the second object.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We can cut a piece of string so it is as long as one object, then we move the string and compare itslength with the second object.

And, we can tell that the second object is slightly longer.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

The length of string has been used as a unit of length.

We were able to move that unit to compare the two objects.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Or, suppose we have two children stand on opposite sides of the room and ask the class which is taller.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We could have a third child stand by one of them,

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We could have a third child stand by one of them, and then stand by the other one.

Then we can see that the second child is taller.

The third child was used as a unit of length.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Or, suppose we we place two objects on opposite sides of the room and ask the class which is taller.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We could have children come forward and stack their spelling books next to the first object.

Then we could have children stack spelling books next to the second object.

By counting the spelling books, we can tell which object is tallest.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

In this example, the thickness of the book is the unit.

This unit is movable.

It is also countable.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

In this example, we can assign a number to each length

We have measured the lengths.

—the numberof books.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

The children need to experience measurement of length using a wide variety of arbitrary units.

The pencil is about six erasers long.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

The children need to experience measurement of length using a wide variety of arbitrary units.

The notebook is about 3 crayons long.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

When children experience many varied examples like these, they develop a clear understanding of how to use units to measure length.

Next, the children must become familiar with standard units of length.

They must understand that there is a need for standard units.

They must develop mental imagery for those standard units.

They must become familiar with the relationships among the standard units.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

They must understand that there is a need for standard units.The need for standard units arises out of the need to be able to communicate a measurement unambiguously to someone else.

If each child is using his or her own foot as a unit of length, then “5 feet long” would mean something different to each child.

To communicate unambiguously about lengths, they must agree on whose foot to use.

That is, they must standardize the unit. Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Examples of standard units that children should be exposed to are inches, feet, yards, meters, centimeters, and so forth.

The customary units (that is, the English empirical units) were standardized for use throughout the British Empire.This allowed British subjects around the world to communicate about measurements without confusion.The metric system originated in France and has become a worldwide system of units. As a result, when metric units are used, the measurements will be understood anywhere in the world.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Children must develop mental imagery for those standard units.

If a typical group of college students are directed to use their hands to show how long a centimeter is, the responses will range from the hands nearly touching to the hands as far apart as the student can reach.This happens because the students do not have a mental image of a centimeter. If we want understanding of the measurement units, we must help the child develop mental referents for those units.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Appropriate referents are not developed from talking about the units.

The children should see that a foot is about the length of a man’s shoe.The children should see that a yard is about as long as the distance from your nose to the end of your fingers when your arm is stretched out.

The children should see that a meter is about the distance that a doorknob is from the floor.

They are developed from seeing the units in relationship to familiar objects.For example,

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

The children must become familiar with the relationships among the standard units.

It develops from making even trades where they see, for example, that when 3 feet are placed end to end, the total length is the same as a yard.

It develops from making comparisons and seeing what lengths are equal and what lengths are not equal.

Again, this familiarity is developed from seeing how the units relate to one another.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Next, the children must develop the ability to estimate lengths.

The child must be able to mentally place those units alongside the object to arrive at the estimated length.

Children cannot develop the ability to estimate lengths unless they have a clear mental image of the unit used in the estimate.

Not surprisingly, this skill develops from a lot of practice.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

The most effective estimation activity is one where, after each estimation, the child receives almost immediate feedback with respect to the accuracy of the estimate.This immediate feedback allows the child to make a mental adjustment before making the next estimate.

That adjustment is an adjustment to the child’s mental image of the unit.

So, the child’s mental image of the unit helps the child make a reasonable estimate, and the immediate feedback on the accuracy of the estimate helps the child improve the mental image of the unit.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

An effective estimation activity would follow this procedure.

Identify a length to be estimated

Estimate the length

Check the estimate

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

An effective estimation activity would follow this procedure.

Identify another

length to be estimated

Estimate the length

Check the estimate

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

And finally, the children must develop proficiency using length-measurement tools.

Those tools might include foot-rulers, yardsticks, meter sticks, tape measures, calipers, and trundle wheels.

Children should be exposed to a wide variety of tools that may be used to measure length.

The children should become familiar with how these tools work.They should become proficient with these tools.

They should understand when each of these tools is the appropriate one to use.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Chapter 10: Measurement:Assigning a Number to a Quantity

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Presentation 10b Developing Area Formulas

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Children learn about area in much the same way that they learn about length.

First, they develop an understanding of what area (the attribute that will be measured) is.

Then they develop the concept of unit of area.

They then learn to measure area by covering the interior of a shape with squares (pieces of area).

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

But then, the children learn something that is very different from what they learned about length.

They learn that area is almost never measured.

Rather, they learn that certain key lengths are measured, and then those lengths are used in a formula to compute the area.

Most of the time spent on area is actually devoted to learning and using those area-computation formulas.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

When teaching the area-computation formulas, there is one big idea that should be emphasized.

Emphasis of this big idea encourages good problem-solving thinking.

Use what you already know to help you figure out what you need to know.

When you want to find the area of a shape for which you do not have a formula, change the shape into one for which you do have a formula.

So, the big idea for teaching and for learning the area-computation formulas is:

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Suppose the children have already learned the area-computation formula for rectangles:

A = l x w or A = b x h

If they must find the area of a parallelogram, they need to see how the formula that they already know can help them.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Suppose a parallelogram has a base of 8 inches and a height of 4 inches. b = 8 in. and h = 4 in.

4 in.

8 in.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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If we cut one end off of the parallelogram to leave a square corner,

4 in.

8 in.

we still have the same total area,

but now it is in two pieces.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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If we rearrange the pieces, we still have the same total area.

4 in.

8 in.

If we move the piece that we cut off of the parallelogram to the other end,

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

If we rearrange the pieces, we still have the same total area.

4 in.

8 in.

If we move the piece that we cut off of the parallelogram to the other end,

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

If we rearrange the pieces, we still have the same total area.

4 in.

8 in.

If we move the piece that we cut off of the parallelogram to the other end,

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

If we rearrange the pieces, we still have the same total area.

4 in.

8 in.

If we move the piece that we cut off of the parallelogram to the other end, we have a rectangle.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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So it turns out that the area of this parallelogram

4 in.

8 in.

is equal to the area of this rectangle.

8 in.

4 in.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

The same process can be used to find the area of any parallelogram.

h

b

The area of a parallelogram with base b and height h

h

b

is equal to the area of a rectangle with base b and height h.

The area of any parallelogram can be found using this formula: A = b x h

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Suppose a triangle has a base of 8 inchesb = 8 in. and h = 7 in.and a height of 7 inches.

8 in.

7 in.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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We do not have a formula for the area of a triangle, so we want to change the triangle into a shape for which we do have an area formula.

First, we will duplicate the triangle.

8 in.

7 in.

Notice that we now have twice as much area.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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Next, we will rotate the second triangle.

8 in.

7 in.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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Next, we will rotate the second triangle.

8 in.

7 in.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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Next, we will rotate the second triangle.

8 in.

7 in.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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Then we will connect the two triangles.

8 in.

7 in.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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Then we will connect the two triangles.

8 in.

7 in.

The new shape is a parallelogram with base b (8 in.) and height h (7 in.). We have a formula for the area of a parallelogram: A = b x h

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Remember that when we doubled the triangle we also doubled the area.

8 in.

7 in.

We have twice as much area as we started with.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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To get rid of the extra area, we can multiply by one half.

8 in.

7 in.

A = b x h12

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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8 in.

7 in.

A = b x h12

To get rid of the extra area, we can multiply by one half. A = b x h1

2

The area of the triangle is12= x 8 x 7 = 28 sq. in.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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Suppose a trapezoid has bases of 10 cmand a height of 4 cm.and 6 cm,

10 cm

6 cm

4 cm

b = 10 cm, b = 6 cm, and h = 4 cm1 2

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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We don’t have a formula for area of a trapezoid, so we will try to change the trapezoid into a shape for which we do have a formula.

10 cm

6 cm

4 cm

We will begin by doubling the trapezoid.

Then we rotate the new piece

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We don’t have a formula for area of a trapezoid, so we will try to change the trapezoid into a shape for which we do have a formula.

10 cm

6 cm

4 cm

We will begin by doubling the trapezoid.

Then we rotate the new piece

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We don’t have a formula for area of a trapezoid, so we will try to change the trapezoid into a shape for which we do have a formula.

10 cm

6 cm

4 cm

We will begin by doubling the trapezoid.

Then we rotate the new piece and connect the twotrapezoids.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

We don’t have a formula for area of a trapezoid, so we will try to change the trapezoid into a shape for which we do have a formula.

10 cm

6 cm

4 cm

We will begin by doubling the trapezoid.

Then we rotate the new piece and connect the twotrapezoids.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

The base of this parallelogram is 6 cm + 10 cm.

10 cm

6 cm

4 cm

The height of the parallelogram is 4 cm. That’s the height of the original trapezoid (h).

That’s the sum of the two bases of the original trapezoid ( + ).b1 b2

We can use the area formula for parallelograms to get this area: A = (b + b )h1 2

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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10 cm

6 cm

4 cm

But remember that when we use this formula to get the area of the parallelogram, we have twice as much area as when we started.

So we must multiply by one half to get the area of the original trapezoid. 1 2A = (b + b )h1

2

We can use the following formula to get the area of our original trapezoid:

2

= 32 cm12= x (10 + 6) x 41 2A = (b + b )h

12Tucker/Singleton/Weaver

Teaching Mathematics to ALL Children, Second EditionCopyright ©2006 by Pearson Education, Inc.

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r

Suppose a circle has a radius of r.

We know that the diameter is twice the radius. d = 2r

The circumference is c = d or c = 2 r. Half the circumference, then, is r.

r

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Suppose we cut the circle into eighths.

The total amount of area is the same.

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If we rearrange the area, the total area is not changed.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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If we rearrange the area, the total area is not changed.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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If we rearrange the area, the total area is not changed.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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If we rearrange the area, the total area is not changed.

Now the shape is a “parallelogram,” but the total area is still the same as the area of the original circle.

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Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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The height of the parallelogram is the same as the radius of the original circle.

r

rAnd, the base of the parallelogram is the same as half the circumference of the original circle.

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Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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To find the area of a parallelogram, we multiply its base times its height.

r

And, this is the formula for the area of a circle:

.A = r r

2= r

A =2

r

r

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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Chapter 11: Geometry:Learning the Names and Characteristics of Shapes

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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Presentation 11 The Big Ideas of Elementary School Geometry

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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There are six attributes that may or may not be present in a geometric figure.

Since these attributes are constantly recurring, they can be used to analyze, describe, and classify shapes.

Although these attributes are complex mathematically, they can be understood informally by young children.

Furthermore, there are simple, child-appropriate ways to test shapes to see if these attributes are present.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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Therefore, we will consider these six attributes to be the big ideas of elementary school geometry:

Straightness

Congruence

Similarity

Parallelism

Perpendicularity

Symmetry

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Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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Straightness is important in the classification of shapes.

In order to name a 2-dimensional figure, children must decide if the sides are straight.

To classify a 3-dimensional shape, children must decide if the edges are straight.

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There are three easy ways for children to check for straightness.

A child might choose to use any one of them, depending on the situation.

First, a child might look along the edge of a shape to see if that edge is straight.

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And, of course, the child can use this method without understanding that it works because light usually travels in a straight line.

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Second, a child might stretch a string along the side of a shape to see if that side is straight.

And, the child would not need to worry about the laws of physics before using this method either.

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Third, a child might fold a sheet of paper and use the folded edge of the paper as a straightedge.

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And, it isn’t necessary for the child to know the the folded edge is straight because it is the intersection of two planes.

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The second big idea, congruence, is also important in the classification of shapes.

Two figures are congruent if they are exactly the same size and shape.

Often it is important to know whether parts of a figure are congruent to each other.

For example, a necessary characteristic of rectangles is that all the angles are congruent.A necessary characteristic of prisms is that both of the bases are congruent.

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The easiest way for children to determine if two shapes are congruent is to trace one of them and see if the tracing fits the other one.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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The easiest way for children to determine if two shapes are congruent is to trace one of them and see if the tracing fits the other one.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

The easiest way for children to determine if two shapes are congruent is to trace one of them and see if the tracing fits the other one.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

The easiest way for children to determine if two shapes are congruent is to trace one of them and see if the tracing fits the other one.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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The third big idea is similarity. Similarity is important for classification of many shapes.

Two figures are similar if they are exactly the same shape.

Two similar figures may be the same size.

If two similar figures are the same size, then they are also congruent.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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When two figures are similar, they will be related in two very important ways.

First, each angle of one figure will be congruent to the corresponding angle of the other figure.

These angles are equal.Tucker/Singleton/Weaver

Teaching Mathematics to ALL Children, Second EditionCopyright ©2006 by Pearson Education, Inc.

Upper Saddle River, New Jersey 07458All rights reserved.

When two figures are similar, they will be related in two very important ways.

First, each angle of one figure will be congruent to the corresponding angle of the other figure.

These angles are equal.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

When two figures are similar, they will be related in two very important ways.

First, each angle of one figure will be congruent to the corresponding angle of the other figure.

These angles are equal.Tucker/Singleton/Weaver

Teaching Mathematics to ALL Children, Second EditionCopyright ©2006 by Pearson Education, Inc.

Upper Saddle River, New Jersey 07458All rights reserved.

When two figures are similar, they will be related in two very important ways.

First, each angle of one figure will be congruent to the corresponding angle of the other figure.

These angles are equal.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

When two figures are similar, they will be related in two very important ways.

First, each angle of one figure will be congruent to the corresponding angle of the other figure.

These angles are equal.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

That means that the ratio of a length in one figure to the corresponding length in the other figure will always be the same.

Second, corresponding lengths will be proportional.

If this length is one half of this length,

then this length will be one half of this length.Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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That means that the ratio of a length in one figure to the corresponding length in the other figure will always be the same.

Second, corresponding lengths will be proportional.

This length will be one half of this length. Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

That means that the ratio of a length in one figure to the corresponding length in the other figure will always be the same.

Second, corresponding lengths will be proportional.

This length will be one half of this length, and so forth.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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One way the children can check two figures to see if they are similar is to hold them with the smaller one close and the larger one far away.

If the two figures are similar, the child can move them forward or backward until the two shapes appear to fit.

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If the two figures are printed on paper and are oriented the same way

If the lines intersect in a single point,

then the two figures are similar.

—the childrencan check for similarity by drawing lines through corresponding points.

—that is, if a pair ofcorresponding sides are parallel

These sides are parallel.Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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The fourth big idea, parallelism, is also important for classification of many shapes.

We can think of parallel lines in several ways.

If parallel lines are in the same plane, they will never intersect.

Parallel lines are the same distance apart no matter where you measure.

Parallel lines go in the same direction.

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Let’s consider these notions about parallelism.

If we draw lines on a sheet of paper, we can only extend those lines to the edge of the paper. We cannot be sure whether they would finally intersect if we extended them a lot farther.

If the lines are drawn on the chalkboard, we cannot be sure whether they might intersect if we could extend them far enough.

Parallel lines never intersect.

So, this idea about parallelism is not helpful, because we cannot check to see if lines will ever intersect.

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This idea about parallelism is easy for children to check.

Parallel lines are the same distance apart no matter where you measure.

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We can lay a sheet of paper on the lines so that an edge coincides with the top line.

Then we use a pencil to mark the distance between the lines.

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By sliding the paper back and forth along the line,

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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By sliding the paper back and forth along the line,

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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By sliding the paper back and forth along the line,

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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By sliding the paper back and forth along the line,

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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By sliding the paper back and forth along the line, we can verify that the distance between thelines is the same wherever we measure it.The lines are parallel.

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This idea about parallelism is also easy for children to check.

Parallel lines go in the same direction.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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We will begin by drawing a line across the two original lines.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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Next, we lay a sheet of paper across the lines with its edge along the line that we added.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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This shows the direction of that original line.

Then, we use a ruler to draw a line on the sheet of paper on top of one of the original lines.

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And finally, we slide the paper down the line that we added to check the direction of the second original line.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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These lines go in the same direction, so they are parallel lines.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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The fifth big idea is perpendicularity, which is also considered when classifying shapes.

The easiest way for children to think of perpendicularity is for them to think about “square corners.”

The children can identify square corners and corners that are not square.

Most children will already have a sense of what square corners are.You can show them corners that are square and corners that are not square.

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Children can make a square corner by folding a sheet of paper twice.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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They can then lay that square corner on top of any other angle (corner) to see if it is also square.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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The sixth big idea is symmetry, another important characteristic of many shapes.

Children often find line symmetry easier to understand than to explain.

Indeed, children often use contradictory language when trying to explain symmetry.

For example, a child might explain that a shape is symmetric when “its two sides are exactly the same except they are opposite.”

There are several types of symmetry, but in the elementary grades the most common type considered is line symmetry.

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This line of symmetry separates the figure into congruent parts.

If a figure has line symmetry, there is a line which separates the figure into two parts.

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We can place a sheet of paper on one side of the line of symmetryshape.

and trace that half of the

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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Then we flip the paper across the line of symmetry to see if the two parts are congruent.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

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Then we flip the paper across the line of symmetry to see if the two parts are congruent.If the two parts are congruent, then the figure has line symmetry.

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Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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Line symmetry is sometimes called folding symmetry.The figure can be folded along the line of symmetry to see if the two parts are congruent.

If the two parts match then the figure is symmetric.

Tucker/Singleton/WeaverTeaching Mathematics to ALL Children, Second Edition

Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

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Activity Trace essential Standard through your text

Video Number of the Day

Make and Take Activity

Tessellations http://www.tessellations.org/index.htm http://gwydir.demon.co.uk/jo/tess/bigtri.htm http://gwydir.demon.co.uk/jo/tess/bighex.htm http://gwydir.demon.co.uk/jo/tess/hexsqtri.htm

Activity

GAME TIME!!!

Each week, students will take turns leading the class in a math game.

Closing Final thoughts, comments? Making connections – Anything to add to

your reflection?