Add 15/21 and 3/18
15/21 + 3/18 is 37/42.
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,
15/21 = 15 × 6/21 × 6 = 90/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
3/18 = 3 × 7/18 × 7 = 21/126 - Add the two like fractions:
90/126 + 21/126 = 90 + 21/126 = 111/126 - 111/126 simplified gives 37/42
- So, 15/21 + 3/18 = 37/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21+3/18 15/21+6/18 15/42+3/18 15/21+3/36 45/21+3/18 15/21+9/18 15/63+3/18 15/21+3/54 75/21+3/18 15/21+15/18 15/21+3/90 15/21+21/18