Add 21/72 and 3/42
21/72 + 3/42 is 61/168.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 42 is 504
Next, find the equivalent fraction of both fractional numbers with denominator 504 - For the 1st fraction, since 72 × 7 = 504,
21/72 = 21 × 7/72 × 7 = 147/504 - Likewise, for the 2nd fraction, since 42 × 12 = 504,
3/42 = 3 × 12/42 × 12 = 36/504 - Add the two like fractions:
147/504 + 36/504 = 147 + 36/504 = 183/504 - 183/504 simplified gives 61/168
- So, 21/72 + 3/42 = 61/168
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/72+3/42 21/72+6/42 21/72+3/84 63/72+3/42 21/72+9/42 21/72+15/42 21/72+21/42