Add 21/42 and 21/20
1st number: 21/42, 2nd number: 1 1/20
21/42 + 21/20 is 31/20.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 42 × 10 = 420,
21/42 = 21 × 10/42 × 10 = 210/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
21/20 = 21 × 21/20 × 21 = 441/420 - Add the two like fractions:
210/420 + 441/420 = 210 + 441/420 = 651/420 - 651/420 simplified gives 31/20
- So, 21/42 + 21/20 = 31/20
In mixed form: 111/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/42+42/20 21/84+21/20 21/42+21/40 63/42+21/20 21/42+63/20 21/42+21/60