math unit 4 lesson 4 relate side lengths with the number of tiles on a side
TRANSCRIPT
Math Unit 4 Lesson 4
Relate side lengths with the number of tiles on a side.
Skip Count!
Skip Count By 6s To 60 … 6 12 18 24 3036 42 48 54 60
Skip Count By 7s To 70 … 7 14 21 28 35
42 49 56 63 70
Skip Count by 8s to 80 … 8 16 24 32 40
48 56 64 72 80
Skip Count by 9s to 90 … 9 18 27 36 45
54 63 72 81 90
Products In an Array
★ ★ ★★ ★ ★★ ★ ★★ ★ ★★ ★ ★
On your white board, write two different multiplication sentences that can be used to find the total number of stars
5 x 3
3 x 5
Products In an Array
★ ★ ★ ★ ★ ★★ ★ ★ ★ ★ ★★ ★ ★ ★ ★ ★★ ★ ★ ★ ★ ★
On your white board, write two different multiplication sentences that can be used to find the total number of stars
4 x 6
6 x 4
Products In an Array
★★★★★★★★★★★★★★★★★★★★★
On your white board, write two different multiplication sentences that can be used to find the total number of stars
7 x 3
3 x 7
Count the Square Units
How many square units are in the rectangle?
8 square units!
Count the Square Units
How many square units are in the rectangle?
8 square units!
Count the Square Units
How many square units are in the rectangle?
8 square units!
Count the Square Units
How many square units are in the rectangle?
8 square units!
Count the Square Units
What do all these rectangles have in
common?
They all have an
area of 8 square
units!
Problem of the Day
Mara’s rectangle has a bigger area because she used more tiles than Ashton.
Mara & Ashton use square centimeter tiles to make rectangles. Mara uses 15 tiles. Ashton uses 9 tiles. Draw what Mara & Ashton’s rectangles might look
like. Whose rectangle has a bigger area? How do you
know?
Mara’s rectangle Ashton’s rectangle
Concept Development
Get out 15 square inch tiles.
Thumbs up when you are
ready!
Form your tiles into a 3 x 5 array.
Push the tiles together to make a rectangle with
no gaps or overlaps.
What is the area of your rectangle?
15 square inches
Concept DevelopmentHere are two rectangles I made using 15 square inch tiles. Is the area of
these rectangles 15 square inches, too?
How do you know?
Concept Development Rectangle A has
an area LARGER than 15 square inches, because there are gaps between the tiles.
Rectangle B has an area SMALLER than 15 square inches, because the tiles overlap.
Concept DevelopmentNow, go back to that nice, neat rectangle YOU made and measure across the top of the rectangle in inches. What is the length of this side
of the rectangle? How many tiles on this side of
the rectangle?
Next measure the shorter side of the rectangle in inches. What is the length of
this side? And how many tiles
on this side?
5 in. = 5 tiles
3 in. = 3 tiles
Concept Development Draw the rectangle on
your white board or inch grid.
Label the SIDE LENGTHS. What are the units for the
sides?
Label the AREA inside the rectangle. What is the unit for the area?
Why are the units different for the sides and the area? We use inches to measure
length … like the sides. We use square inches to
measure area … or the flat space a figure takes up.
5 inches
3 inche
s
15 square inches
Problem Set!
Let’s figure it out!