Subtract 15/8 from 21/72
1st number: 21/72, 2nd number: 1 7/8
21/72 - 15/8 is -19/12.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 8 is 72
Next, find the equivalent fraction of both fractional numbers with denominator 72 - For the 1st fraction, since 72 × 1 = 72,
21/72 = 21 × 1/72 × 1 = 21/72 - Likewise, for the 2nd fraction, since 8 × 9 = 72,
15/8 = 15 × 9/8 × 9 = 135/72 - Subtract the two like fractions:
21/72 - 135/72 = 21 - 135/72 = -114/72 - After reducing the fraction, the answer is -19/12
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/72-15/8 21/72-30/8 21/72-15/16 63/72-15/8 21/72-45/8 21/72-15/24 21/72-75/8 21/72-15/40 21/72-15/56