Multiplying And Dividing Decimals (Page 2 of 3) in pdf

When multiplying or dividing a decimal by a power of 10, use the exponent to decide how

many places to move the decimal point.

When you multiply by a power of 10, use the exponent to decide how many places to move

the decimal point to the right.

For example,

6.32 x 10¹ = 63.2

- - - - - - - - -move the decimal point one place to the right

6.32 x 10² = 632

- - - - - - - - -move the decimal point two places to the right

6.32 x 10³ = 6,320 - - - - - - - - -move the decimal point three places to the right

When you divide a decimal by a power of 10, use the exponent to decide how many places to

move the decimal point to the left.

For example,

6.32 ÷ 10¹ = 0.632

- - - - - - - - -move the decimal point one place to the left

6.32 ÷ 10² = 0.0632 - - - - - - - - -move the decimal point two places to the left

6.32 ÷ 10³ = 0.00632 - - - - - - - - -move the decimal point three places to the left

 Example 4. What is the product?

0.3 x 10² = ⃝

Strategy: Multiply by a power of 10.

Step 1. Decide in which direction to move the decimal point. You are multiplying by a

power of 10, so you move the decimal point to the right.

Step 2. Find the number of places to move the decimal point in the product. The exponent

tells how many places to move to the right. The exponent is 2, so move the decimal point

2 places.

Step 3. Write the product. Move the decimal point on 0.3 two places to the right. Fill the

empty places with zeros. 0.30.

Solution: 0.3 x 10² = 30

 Example 5. What is the quotient? 627.4 ÷ 10³ = ⃝

Strategy: Divide by a power of 10.

Step 1. Decide in which direction to move the decimal point. You are dividing by a

power of 10, so move the decimal point to the left.

Step 2. Find the number of places to move the decimal point in the quotient. The

exponent tells how many places to move to the left. The exponent is 3, so move the

decimal point 3 places.

Step 3. Write the quotient. Move the decimal point in 627.4 three places to the left. Write

a leading zero. .627.4

Solution:

627.4 ÷ 10³ = 0.6274

Tuesday, November 13, 2012 Parent Signature ______________________________(1-5)

(1) What is 243 multiplied by 10? (A) 24.3 (B) 2,430 (C) 24,300 (D) 243,000

(2) What is 85 multiplied by 0.01? (A) 850 (B) 8.5

(D) 0.085

(3) How many zeros are in the product of 11 x 10⁴? __________

(4) How many places to the left do you move the decimal point in 4.8 to find the

quotient of 4.8 ÷ 10²? ____________

(5) Explain what happens to the value of each place as you move from right to left on a

place-value chart. _______________________________________________________

Multiplying And Dividing Decimals Page 2

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