Add 7/8 and 21/30
7/8 + 21/30 is 63/40.
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,
7/8 = 7 × 15/8 × 15 = 105/120 - Likewise, for the 2nd fraction, since 30 × 4 = 120,
21/30 = 21 × 4/30 × 4 = 84/120 - Add the two like fractions:
105/120 + 84/120 = 105 + 84/120 = 189/120 - 189/120 simplified gives 63/40
- So, 7/8 + 21/30 = 63/40
In mixed form: 123/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 14/8+21/30 7/8+42/30 7/16+21/30 7/8+21/60 21/8+21/30 7/8+63/30 7/24+21/30 7/8+21/90 35/8+21/30 7/40+21/30 49/8+21/30 7/56+21/30