Arrays and Expanded Algorithm

EQ: How can arrays help you multiply 2 digit numbers?

Multiply Using an Array

There are 13 bobble head dogs in each row of the carnival booth. There are 24 equal rows. How many dogs are there?

Use R.I.F.F.S to assist you. Draw an array for

24 x 13 Separate each factor into tens and ones. (write in

expanded form)

(20 + 4) x 10

Use the distributive property to solve.

(20 + 4) x 3

Use the distributive property to solve.

Find the number of squares in each rectangle.

20

10

4

10

20

3

4

3

200

40

60

12

Add the partial products 200 60 40 + 12

21

1

3

20 x 10 + 4 x 10 20 x 3 + 4 x 3

26 x 24 Checklist

Write factors in expanded form (separate tens and ones)

(20 + 6) x 20 and (20 +6) x 4 Use the distributive

property 20 x 20 20 x 6 20 x 4 6 x 4 Add all partial products

Circle your answer

400

120

80

24

400120 80

+ 24_ 42

1

6

12 x 14Checklist

Write factors in expanded form (separate tens and ones)

Use the distributive property

Add all partial products Circle your answer

100

20

40

8100 20 40

+ 8_ 168

18 x 26Checklist

Write factors in expanded form (separate tens and ones)

Use the distributive property

Add all partial products Circle your answer 200 160

60 48

200 160 60

+ 48_468

1