1. Lesson 4.5 Multiplying and Dividing by Powers of 10.
Goal: The learner will use mental math to multiply and divide.

2. What happens when you multiply by a power of 10?
Whole Number Powers of Ten
Decimal Powers of Ten
10 x 8.3 =
0.10 x 8.3 =
100 x 8.3 =
0.01 x 8.3 =
1000 x 8.3 =
0.001 x 8.3 =
10,000 x 8.3 =
x 8.3 =

3. Multiplying by whole number powers of ten: Move the decimal point one point to the right for every zero.
Multiplying by decimal powers of ten: Move the decimal point one point to the left for every zero.
The Rules

4. 0.05 x 1000 =
95.38 x =

5. The graph shows the number of vehicles that crossed bridges during How many vehicles crossed the Golden Gate Bridge?

6. Dividing by Powers of Ten
Whole Number Powers: Move the decimal point to the left for each zero.
Decimal Number Powers: Move the decimal point to the right for each zero.
Dividing by Powers of Ten

7. 508.3÷ 10
508.3 ÷ 0.01
Examples

8. Go to Classzone and complete the
section 4.5 quiz under assessments.