Add 15/18 and 3/21
15/18 + 3/21 is 41/42.
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,
15/18 = 15 × 7/18 × 7 = 105/126 - Likewise, for the 2nd fraction, since 21 × 6 = 126,
3/21 = 3 × 6/21 × 6 = 18/126 - Add the two like fractions:
105/126 + 18/126 = 105 + 18/126 = 123/126 - 123/126 simplified gives 41/42
- So, 15/18 + 3/21 = 41/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/18+3/21 15/18+6/21 15/36+3/21 15/18+3/42 45/18+3/21 15/18+9/21 15/54+3/21 15/18+3/63 75/18+3/21 15/18+15/21 15/90+3/21