Add 72/21 and 12/18
1st number: 3 9/21, 2nd number: 12/18
72/21 + 12/18 is 86/21.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 21 × 6 = 126,
72/21 = 72 × 6/21 × 6 = 432/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
12/18 = 12 × 7/18 × 7 = 84/126 - Add the two like fractions:
432/126 + 84/126 = 432 + 84/126 = 516/126 - 516/126 simplified gives 86/21
- So, 72/21 + 12/18 = 86/21
In mixed form: 42/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/21+24/18 72/42+12/18 72/21+12/36 72/21+36/18 72/63+12/18 72/21+12/54 72/21+60/18 72/21+12/90 72/21+84/18