Subtract 21/84 from 3/28
3/28 - 21/84 is -1/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 84 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 28 × 3 = 84,
3/28 = 3 × 3/28 × 3 = 9/84 - Likewise, for the 2nd fraction, since 84 × 1 = 84,
21/84 = 21 × 1/84 × 1 = 21/84 - Subtract the two like fractions:
9/84 - 21/84 = 9 - 21/84 = -12/84 - After reducing the fraction, the answer is -1/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/28-21/84 3/28-42/84 3/56-21/84 9/28-21/84 3/28-63/84 3/84-21/84 15/28-21/84 21/28-21/84