Add 15/30 and 21/7
1st number: 15/30, 2nd number: 3 0/7
15/30 + 21/7 is 7/2.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 7 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 30 × 7 = 210,
15/30 = 15 × 7/30 × 7 = 105/210 - Likewise, for the 2nd fraction, since 7 × 30 = 210,
21/7 = 21 × 30/7 × 30 = 630/210 - Add the two like fractions:
105/210 + 630/210 = 105 + 630/210 = 735/210 - 735/210 simplified gives 7/2
- So, 15/30 + 21/7 = 7/2
In mixed form: 31/2
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 15/30+42/7 15/60+21/7 15/30+21/14 45/30+21/7 15/30+63/7 15/90+21/7 75/30+21/7 15/30+21/35 15/30+21/49