Add 21/40 and 28/20
1st number: 21/40, 2nd number: 1 8/20
21/40 + 28/20 is 77/40.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 20 is 40
Next, find the equivalent fraction of both fractional numbers with denominator 40 - For the 1st fraction, since 40 × 1 = 40,
21/40 = 21 × 1/40 × 1 = 21/40 - Likewise, for the 2nd fraction, since 20 × 2 = 40,
28/20 = 28 × 2/20 × 2 = 56/40 - Add the two like fractions:
21/40 + 56/40 = 21 + 56/40 = 77/40 - So, 21/40 + 28/20 = 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: 42/40+28/20 21/40+56/20 21/80+28/20 21/40+28/40 63/40+28/20 21/40+84/20 21/40+28/60