Multiplying by Groups of Ten

Strategies to Multiply by Multiples of 10

Place Value and Associative Property

Use Place Value and Associative Property

• Break apart the multiple of 10 into a one and ten

• Put parentheses around the ones

• Multiply the ones

• Multiply the ones by ten

Use Place Value and Associative Property

• Step 1: break apart the 50 into 5 x 10

• Step 2: Put parentheses around the ones (2 x 5)

• Step 3: Multiply the ones (2 x 5) = 10

• Step 4: Multiply 10 x 10

Let's Practice

• 3 x 40

• Break apart the 40 into 4 x 10

• Put the ones in parentheses (3 x 4)

• Solve (3 x 4)

Fill in the Blanks

3 x 4 =

ones

Multiple Choice

12 x 10

• 1200

• 120

• 200

Let's Practice

• Step one: break apart 30 into 3 x 10

• Step two: put parentheses around the ones

Fill in the Blanks

Put parentheses around the ones

Fill in the Blanks

Multiply 2 x 3

Fill in the Blanks

2 x 30 =

(2 x 3) x 10 =

6 x 10 =

Fill in the Blanks

Put parentheses around the ones

Fill in the Blanks

3 x 5 =

Multiple Choice

15 x 10 =

• 1500

• 151

• 150

• 500

Fill in the Blanks

4 x 5 =

ones

Multiple Choice

20 x 10 =

• 20

• 200

• 2000

• 120

Multiple Choice

what do we do first?

• put parentheses around the ones

• Multiply the ones times tens

• break apart the ten

Multiple Choice

Where do we put the parentheses?

• Around the ones

• Around the one and tens

Poll

Is it easier to think about multiplying by ones then add a zero or break apart the ten and use associative property?

• Think about multiplying the ones then add a zero

• Break apart the ten and use associative property