Add 12/21 and 9/18
12/21 + 9/18 is 15/14.
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,
12/21 = 12 × 6/21 × 6 = 72/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
9/18 = 9 × 7/18 × 7 = 63/126 - Add the two like fractions:
72/126 + 63/126 = 72 + 63/126 = 135/126 - 135/126 simplified gives 15/14
- So, 12/21 + 9/18 = 15/14
In mixed form: 11/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/21+9/18 12/42+9/18 12/21+9/36 36/21+9/18 12/21+27/18 12/63+9/18 12/21+9/54 60/21+9/18 12/21+45/18 12/21+9/90 84/21+9/18 12/21+63/18