Add 15/90 and 21/30
15/90 + 21/30 is 13/15.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 30 is 90
Next, find the equivalent fraction of both fractional numbers with denominator 90 - For the 1st fraction, since 90 × 1 = 90,
15/90 = 15 × 1/90 × 1 = 15/90 - Likewise, for the 2nd fraction, since 30 × 3 = 90,
21/30 = 21 × 3/30 × 3 = 63/90 - Add the two like fractions:
15/90 + 63/90 = 15 + 63/90 = 78/90 - 78/90 simplified gives 13/15
- So, 15/90 + 21/30 = 13/15
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/90+21/30 15/90+42/30 15/90+21/60 45/90+21/30 15/90+63/30 15/90+21/90 75/90+21/30