Add 21/30 and 81/70
1st number: 21/30, 2nd number: 1 11/70
21/30 + 81/70 is 13/7.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 70 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 30 × 7 = 210,
21/30 = 21 × 7/30 × 7 = 147/210 - Likewise, for the 2nd fraction, since 70 × 3 = 210,
81/70 = 81 × 3/70 × 3 = 243/210 - Add the two like fractions:
147/210 + 243/210 = 147 + 243/210 = 390/210 - 390/210 simplified gives 13/7
- So, 21/30 + 81/70 = 13/7
In mixed form: 16/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/30+81/70 21/60+81/70 63/30+81/70 21/90+81/70