Subtract 21/8 from 30/15
1st number: 2 0/15, 2nd number: 2 5/8
30/15 - 21/8 is -5/8.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 15 and 8 is 120
Next, find the equivalent fraction of both fractional numbers with denominator 120 - For the 1st fraction, since 15 × 8 = 120,
30/15 = 30 × 8/15 × 8 = 240/120 - Likewise, for the 2nd fraction, since 8 × 15 = 120,
21/8 = 21 × 15/8 × 15 = 315/120 - Subtract the two like fractions:
240/120 - 315/120 = 240 - 315/120 = -75/120 - After reducing the fraction, the answer is -5/8
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/15-21/8 30/15-42/8 30/15-21/16 90/15-21/8 30/15-63/8 30/45-21/8 30/15-21/24 30/75-21/8 30/15-21/40 30/15-21/56