Add 15/21 and 8/7
1st number: 15/21, 2nd number: 1 1/7
15/21 + 8/7 is 13/7.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 7 is 21
Next, find the equivalent fraction of both fractional numbers with denominator 21 - For the 1st fraction, since 21 × 1 = 21,
15/21 = 15 × 1/21 × 1 = 15/21 - Likewise, for the 2nd fraction, since 7 × 3 = 21,
8/7 = 8 × 3/7 × 3 = 24/21 - Add the two like fractions:
15/21 + 24/21 = 15 + 24/21 = 39/21 - 39/21 simplified gives 13/7
- So, 15/21 + 8/7 = 13/7
In mixed form: 16/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21+8/7 15/21+16/7 15/42+8/7 15/21+8/14 45/21+8/7 15/21+24/7 15/63+8/7 15/21+8/21 75/21+8/7 15/21+40/7 15/21+8/35 15/21+56/7 15/21+8/49