Add 15/8 and 21/30
1st number: 1 7/8, 2nd number: 21/30
15/8 + 21/30 is 103/40.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 30 is 120
Next, find the equivalent fraction of both fractional numbers with denominator 120 - For the 1st fraction, since 8 × 15 = 120,
15/8 = 15 × 15/8 × 15 = 225/120 - Likewise, for the 2nd fraction, since 30 × 4 = 120,
21/30 = 21 × 4/30 × 4 = 84/120 - Add the two like fractions:
225/120 + 84/120 = 225 + 84/120 = 309/120 - 309/120 simplified gives 103/40
- So, 15/8 + 21/30 = 103/40
In mixed form: 223/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/8+21/30 15/8+42/30 15/16+21/30 15/8+21/60 45/8+21/30 15/8+63/30 15/24+21/30 15/8+21/90 75/8+21/30 15/40+21/30 15/56+21/30