Add 18/20 and 63/21
1st number: 18/20, 2nd number: 3 0/21
18/20 + 63/21 is 39/10.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 21 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 20 × 21 = 420,
18/20 = 18 × 21/20 × 21 = 378/420 - Likewise, for the 2nd fraction, since 21 × 20 = 420,
63/21 = 63 × 20/21 × 20 = 1260/420 - Add the two like fractions:
378/420 + 1260/420 = 378 + 1260/420 = 1638/420 - 1638/420 simplified gives 39/10
- So, 18/20 + 63/21 = 39/10
In mixed form: 39/10
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/20+63/21 18/40+63/21 18/20+63/42 54/20+63/21 18/60+63/21 90/20+63/21