Subtract 7/15 from 21/40
21/40 - 7/15 is 7/120.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 15 is 120
Next, find the equivalent fraction of both fractional numbers with denominator 120 - For the 1st fraction, since 40 × 3 = 120,
21/40 = 21 × 3/40 × 3 = 63/120 - Likewise, for the 2nd fraction, since 15 × 8 = 120,
7/15 = 7 × 8/15 × 8 = 56/120 - Subtract the two like fractions:
63/120 - 56/120 = 63 - 56/120 = 7/120
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/40-7/15 21/40-14/15 21/80-7/15 21/40-7/30 63/40-7/15 21/40-21/15 21/40-7/45 21/40-35/15 21/40-7/75 21/40-49/15