Module 7 Lesson 12Measure side lengths in whole number units

to determine the perimeter of polygons.

Perimeter: The distance around a two-dimensional shape.

Multiply by 7

7 x 7 = _____

Let’s skip-count up by Sevens to find the answer. Hold up a finger for each seven.

7 14 28 35

49

49 9 x 7 = _____63

Let’s see how we can skip-count start at 35. Start by holding up five fingers. Raise one more finger each time we count.

6 x 7 = _____42

21

56 63 7042

Let’s see how we can skip-count down from 70. Start by holding up 10 fingers. Put down one finger each time we count down.

Multiply by 7 Pattern Sheet

2 minutes

End

Equivalent CountingWith Units of 3

3 6 9 12 15 18 21 24 27 30

1 three

2 threes

3 threes

4 threes

5 threes

6 threes

7 threes

8 threes

9 threes

10 threes

1 x 3=3

2 x 3=6

3 x 3=9

4 x 3=12

5 x 3=15

6 x 3=18

7 x 3=21

8 x 3=24

9 x 3=27

10x3=30

First let’s skip count by three 10 times.

Now let’s count up to 10 groups of 3, or 10 threes.

And last, let’s say the multiplication sentences!

Area & Perimeter

Let’s draw a rectangle that is 2 units wide by 3 units long.

What is the area of the rectangle?6 SQUARE

UNITS

Area & Perimeter

Let’s draw a rectangle that is 2 units wide by 4 units long.

What is the area of the rectangle?8 SQUARE

UNITS

Area & Perimeter

Let’s draw a rectangle that is 3 units wide by 5 units long.

What is the area of the rectangle?15 SQUARE

UNITS

Concept Development

We have learned that the “boundary” of a shape is the shape’s perimeter. Discuss with your partner: What forms the boundary of this shape?

That’s right! The sides of the shape form the boundary.

Concept Development

What can we use to measure the perimeter of this shape? A ruler!

Concept Development

10 cm

10 cm

4 cm4 cm

Let’s write a number sentence to tell us the perimeter of the shape.10 + 10 + 4 + 4 = _____________10 + 10 + 4 + 4 = 28

cm

Concept Development

Let’s try it again!I will pass out the lesson template. Get out your ruler. Measure the sides and calculate the perimeter of each shape.We have already measured shape A.

Measure to the nearest centimeter.

Concept Development

3 cm

5 cm

4 cm

Perimeter: 3 + 4 + 5 = 12 cm

Concept Development

3 cm 3 cm

6 cm

Perimeter: 3 + 3 + 4 + 4 + 6 = 20 cm

4 cm 4 cm

Concept Development

7 cm

Perimeter: 7 + 4 + 7 + 4 = 22 cm

4 cm4 cm

7 cm

Concept Development

6 cm

Perimeter: 8 + 6 + 6 + 3 + 2 + 3 = 28 cm

3 cm

6 cm

8 cm

3 cm

2 cm

Try it Out!

At lunch, Angela measure the sides of a square napkin. Each side measures 6 inches. What is the perimeter of the napkin?

6 inches

6 x 4 = 24.The perimeter of the napkin is 24 inches.

Problem Set

Hi – YA!!