Subtract 18/8 from 21/28
1st number: 21/28, 2nd number: 2 2/8
21/28 - 18/8 is -3/2.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 8 is 56
Next, find the equivalent fraction of both fractional numbers with denominator 56 - For the 1st fraction, since 28 × 2 = 56,
21/28 = 21 × 2/28 × 2 = 42/56 - Likewise, for the 2nd fraction, since 8 × 7 = 56,
18/8 = 18 × 7/8 × 7 = 126/56 - Subtract the two like fractions:
42/56 - 126/56 = 42 - 126/56 = -84/56 - After reducing the fraction, the answer is -3/2
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28-18/8 21/28-36/8 21/56-18/8 21/28-18/16 63/28-18/8 21/28-54/8 21/84-18/8 21/28-18/24 21/28-90/8 21/28-18/40 21/28-18/56