Add 15/21 and 21/8
1st number: 15/21, 2nd number: 2 5/8
15/21 + 21/8 is 187/56.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 8 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 21 × 8 = 168,
15/21 = 15 × 8/21 × 8 = 120/168 - Likewise, for the 2nd fraction, since 8 × 21 = 168,
21/8 = 21 × 21/8 × 21 = 441/168 - Add the two like fractions:
120/168 + 441/168 = 120 + 441/168 = 561/168 - 561/168 simplified gives 187/56
- So, 15/21 + 21/8 = 187/56
In mixed form: 319/56
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21+21/8 15/21+42/8 15/42+21/8 15/21+21/16 45/21+21/8 15/21+63/8 15/63+21/8 15/21+21/24 75/21+21/8 15/21+21/40 15/21+21/56