Add 9/12 and 72/21
1st number: 9/12, 2nd number: 3 9/21
9/12 + 72/21 is 117/28.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 21 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 12 × 7 = 84,
9/12 = 9 × 7/12 × 7 = 63/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
72/21 = 72 × 4/21 × 4 = 288/84 - Add the two like fractions:
63/84 + 288/84 = 63 + 288/84 = 351/84 - 351/84 simplified gives 117/28
- So, 9/12 + 72/21 = 117/28
In mixed form: 45/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 18/12+72/21 9/24+72/21 9/12+72/42 27/12+72/21 9/36+72/21 9/12+72/63 45/12+72/21 9/60+72/21 63/12+72/21 9/84+72/21