Add 18/21 and 63/90
18/21 + 63/90 is 109/70.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 21 × 30 = 630,
18/21 = 18 × 30/21 × 30 = 540/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
63/90 = 63 × 7/90 × 7 = 441/630 - Add the two like fractions:
540/630 + 441/630 = 540 + 441/630 = 981/630 - 981/630 simplified gives 109/70
- So, 18/21 + 63/90 = 109/70
In mixed form: 139/70
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/21+63/90 18/42+63/90 54/21+63/90 18/63+63/90 90/21+63/90