Add 72/18 and 12/21
1st number: 4 0/18, 2nd number: 12/21
72/18 + 12/21 is 32/7.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 21 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 18 × 7 = 126,
72/18 = 72 × 7/18 × 7 = 504/126 - Likewise, for the 2nd fraction, since 21 × 6 = 126,
12/21 = 12 × 6/21 × 6 = 72/126 - Add the two like fractions:
504/126 + 72/126 = 504 + 72/126 = 576/126 - 576/126 simplified gives 32/7
- So, 72/18 + 12/21 = 32/7
In mixed form: 44/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/18+24/21 72/36+12/21 72/18+12/42 72/18+36/21 72/54+12/21 72/18+12/63 72/18+60/21 72/90+12/21 72/18+84/21