- Example:

- Solution:
- The denominator of the first fraction is 6, and 6 = 2 × 3
- The denominator of the second fraction is 10, and 10 = 2 × 5
- Thus, the least common denominator (LCD) is 2 × 3 × 5 = 30

- Note:
- The denominators of the fractions can not be zero.

- Formula to subtract two fractions:
- a/b - c/d = (ad - cb)/bd, in which the denominators b and d can not be zero