Add 21/84 and 9/90
21/84 + 9/90 is 7/20.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 90 is 1260
Next, find the equivalent fraction of both fractional numbers with denominator 1260 - For the 1st fraction, since 84 × 15 = 1260,
21/84 = 21 × 15/84 × 15 = 315/1260 - Likewise, for the 2nd fraction, since 90 × 14 = 1260,
9/90 = 9 × 14/90 × 14 = 126/1260 - Add the two like fractions:
315/1260 + 126/1260 = 315 + 126/1260 = 441/1260 - 441/1260 simplified gives 7/20
- So, 21/84 + 9/90 = 7/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/84+9/90 21/84+18/90 63/84+9/90 21/84+27/90 21/84+45/90 21/84+63/90