Long division is the standard textbook method for converting fractions to decimals, but for many fractions, long division is completely unnecessary. Instead, teach your students the Power of 10 method.
The Secret: Make the Bottom 10, 100, or 1,000
Our decimal system is built on tenths, hundredths, and thousandths. If you can scale the bottom number to 10 or 100 using multiplication, the decimal writes itself!
Example 1: Converting 3/5
- Can we turn 5 into 10? Yes, multiply by 2!
- Multiply top and bottom by 2:
(3 × 2) / (5 × 2) = 6/10 - 6 tenths is written as 0.6. Done!
Example 2: Converting 7/20
- Can we turn 20 into 100? Yes, multiply by 5!
- Multiply top and bottom:
(7 × 5) / (20 × 5) = 35/100 - 35 hundredths is written as 0.35!
Example 3: Converting 13/25
- Multiply by 4:
(13 × 4) / (25 × 4) = 52/100 = 0.52.