1. Multiplying and Dividing Decimals

2. Learning Objectives
Multiply and divide whole numbers and decimals by powers of ten.

3. Answers
A) 35 x 10 = 350
B) x 10 = 13
A) 45 x 100 = 4500
B) 3.33 x 100 = 333
A) 360 ÷ 10 = 36
B) ÷ 10 = 3.515
A) 5500 ÷ 100 = 55
B) ÷ 100 =

4. Answers 10 times bigger 100 times smaller To the right To the left
When a number is multiplied by 10, the number becomes:
10 times bigger
2) When a number is divided by 100, the number becomes:
100 times smaller
3) When a decimal number is multiplied by a power of 10, the decimal point moves:
To the right
4) When a decimal number is divided by a power of 10, the decimal point moves:
To the left

5. RULES
When multiplying by a power of ten, move the decimal to the right.
1) Count the number of zeros in the power of ten
2) move the decimal point to the right, by that number
(add zeros if necessary)

6. RULES When dividing by a power of ten, move the decimal to the left.
1) Count the number of zeros in the power of ten
2) move the decimal point to the left, by that number
(add zeros if necessary)

7. MR: Multiplication  Right
DULL (DL) : Division  Left

8. Multiplying with Decimals
Ignore the decimal point
Do the multiplication
Count the decimal places altogether and put the decimal point back in (from the right)
6 x 0.2
6 x 2 = 12
1 decimal place
6 x 0.2 = 1.2