Subtract 24/28 from 20/21
20/21 - 24/28 is 2/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 28 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
20/21 = 20 × 4/21 × 4 = 80/84 - Likewise, for the 2nd fraction, since 28 × 3 = 84,
24/28 = 24 × 3/28 × 3 = 72/84 - Subtract the two like fractions:
80/84 - 72/84 = 80 - 72/84 = 8/84 - After reducing the fraction, the answer is 2/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/21-24/28 20/21-48/28 20/42-24/28 20/21-24/56 60/21-24/28 20/21-72/28 20/63-24/28 20/21-24/84