Subtract 21/72 from 3/18
3/18 - 21/72 is -1/8.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 72 is 72
Next, find the equivalent fraction of both fractional numbers with denominator 72 - For the 1st fraction, since 18 × 4 = 72,
3/18 = 3 × 4/18 × 4 = 12/72 - Likewise, for the 2nd fraction, since 72 × 1 = 72,
21/72 = 21 × 1/72 × 1 = 21/72 - Subtract the two like fractions:
12/72 - 21/72 = 12 - 21/72 = -9/72 - After reducing the fraction, the answer is -1/8
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/18-21/72 3/18-42/72 3/36-21/72 9/18-21/72 3/18-63/72 3/54-21/72 15/18-21/72 3/90-21/72 21/18-21/72