Add 20/21 and 21/24
20/21 + 21/24 is 307/168.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 24 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 21 × 8 = 168,
20/21 = 20 × 8/21 × 8 = 160/168 - Likewise, for the 2nd fraction, since 24 × 7 = 168,
21/24 = 21 × 7/24 × 7 = 147/168 - Add the two like fractions:
160/168 + 147/168 = 160 + 147/168 = 307/168 - So, 20/21 + 21/24 = 307/168
In mixed form: 1139/168
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/21+21/24 20/21+42/24 20/42+21/24 20/21+21/48 60/21+21/24 20/21+63/24 20/63+21/24 20/21+21/72