Add 42/15 and 21/8
1st number: 2 12/15, 2nd number: 2 5/8
42/15 + 21/8 is 217/40.
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,
42/15 = 42 × 8/15 × 8 = 336/120 - Likewise, for the 2nd fraction, since 8 × 15 = 120,
21/8 = 21 × 15/8 × 15 = 315/120 - Add the two like fractions:
336/120 + 315/120 = 336 + 315/120 = 651/120 - 651/120 simplified gives 217/40
- So, 42/15 + 21/8 = 217/40
In mixed form: 517/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/15+21/8 42/15+42/8 42/30+21/8 42/15+21/16 42/15+63/8 42/45+21/8 42/15+21/24 42/75+21/8 42/15+21/40 42/15+21/56