Dividing by powers of ten
Dividing by powers of ten means making a number 10, 100, 1000, and so on times smaller. Because powers of ten are built from 10s, the decimal point moves to the left when you divide.
Method
- Identify the power of ten in the divisor: 10, 100, 1000, etc.
- Count the zeros in that number.
- Move the decimal point left by the same number of places.
- ÷10 → move 1 place
- ÷100 → move 2 places
- ÷1000 → move 3 places
- If needed, add zeros in front of the number to keep the decimal move accurate.
Example idea
- 456 ÷ 10 = 45.6
- 7.2 ÷ 100 = 0.072
Check your answer
A quick check is to multiply your result by the original power of ten. If you get back the starting number, the division is correct.
Common mistakes
- Moving the decimal point the wrong direction
- Forgetting to add placeholder zeros
- Stopping one place too soon or going one place too far
Keep answers exact and simplified. When the divisor is a power of ten, the decimal move is the main tool you need.