Subtract 21/18 from 4/8
1st number: 4/8, 2nd number: 1 3/18
4/8 - 21/18 is -2/3.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 18 is 72
Next, find the equivalent fraction of both fractional numbers with denominator 72 - For the 1st fraction, since 8 × 9 = 72,
4/8 = 4 × 9/8 × 9 = 36/72 - Likewise, for the 2nd fraction, since 18 × 4 = 72,
21/18 = 21 × 4/18 × 4 = 84/72 - Subtract the two like fractions:
36/72 - 84/72 = 36 - 84/72 = -48/72 - After reducing the fraction, the answer is -2/3
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 4/8-42/18 4/16-21/18 4/8-21/36 12/8-21/18 4/8-63/18 4/24-21/18 4/8-21/54 20/8-21/18 4/40-21/18 4/8-21/90 28/8-21/18 4/56-21/18