Add 18/12 and 72/21
1st number: 1 6/12, 2nd number: 3 9/21
18/12 + 72/21 is 69/14.
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,
18/12 = 18 × 7/12 × 7 = 126/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
72/21 = 72 × 4/21 × 4 = 288/84 - Add the two like fractions:
126/84 + 288/84 = 126 + 288/84 = 414/84 - 414/84 simplified gives 69/14
- So, 18/12 + 72/21 = 69/14
In mixed form: 413/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/12+72/21 18/24+72/21 18/12+72/42 54/12+72/21 18/36+72/21 18/12+72/63 90/12+72/21 18/60+72/21 18/84+72/21