Learn it
Multiply (or divide) the numerator and denominator by the same number to get an equivalent fraction. It is like cutting every piece into the same number of smaller pieces.
2/3 = (2 × 4)/(3 × 4) = 8/12.
Dividing both by a common factor simplifies a fraction: 10/15 = 2/3 (divide both by 5).
Worked examples
Example 1
Write 3/5 with a denominator of 20.
- 5 × 4 = 20, so multiply both parts by 4
- 3 × 4 = 12
Answer: 12/20
Example 2
Simplify 12/18.
- Both 12 and 18 can be divided by 6
- 12 ÷ 6 = 2, 18 ÷ 6 = 3
Answer: 2/3
Practice
Try these on paper first, then check your work.
- 1/4 = ?/12
- 5/6 = ?/18
- Simplify 8/10
- Simplify 9/12
Show the answer key
- 3
- 15
- 4/5
- 3/4