Add 21/15 and 21/40
1st number: 1 6/15, 2nd number: 21/40
21/15 + 21/40 is 77/40.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 15 and 40 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 40 × 3 = 120,
21/40 = 21 × 3/40 × 3 = 63/120 - Add the two like fractions:
168/120 + 63/120 = 168 + 63/120 = 231/120 - 231/120 simplified gives 77/40
- So, 21/15 + 21/40 = 77/40
In mixed form: 137/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/15+21/40 21/15+42/40 21/30+21/40 21/15+21/80 63/15+21/40 21/15+63/40 21/45+21/40 21/75+21/40