Add 21/15 and 9/8
1st number: 1 6/15, 2nd number: 1 1/8
21/15 + 9/8 is 101/40.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 15 and 8 is 120
Next, find the equivalent fraction of both fractional numbers with denominator 120 - For the 1st fraction, since 15 × 8 = 120,
21/15 = 21 × 8/15 × 8 = 168/120 - Likewise, for the 2nd fraction, since 8 × 15 = 120,
9/8 = 9 × 15/8 × 15 = 135/120 - Add the two like fractions:
168/120 + 135/120 = 168 + 135/120 = 303/120 - 303/120 simplified gives 101/40
- So, 21/15 + 9/8 = 101/40
In mixed form: 221/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/15+9/8 21/15+18/8 21/30+9/8 21/15+9/16 63/15+9/8 21/15+27/8 21/45+9/8 21/15+9/24 21/15+45/8 21/75+9/8 21/15+9/40 21/15+63/8 21/15+9/56