Add 72/21 and 15/30
1st number: 3 9/21, 2nd number: 15/30
72/21 + 15/30 is 55/14.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 30 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 21 × 10 = 210,
72/21 = 72 × 10/21 × 10 = 720/210 - Likewise, for the 2nd fraction, since 30 × 7 = 210,
15/30 = 15 × 7/30 × 7 = 105/210 - Add the two like fractions:
720/210 + 105/210 = 720 + 105/210 = 825/210 - 825/210 simplified gives 55/14
- So, 72/21 + 15/30 = 55/14
In mixed form: 313/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/42+15/30 72/21+15/60 72/21+45/30 72/63+15/30 72/21+15/90 72/21+75/30