Add 21/72 and 30/42
21/72 + 30/42 is 169/168.
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,
30/42 = 30 × 12/42 × 12 = 360/504 - Add the two like fractions:
147/504 + 360/504 = 147 + 360/504 = 507/504 - 507/504 simplified gives 169/168
- So, 21/72 + 30/42 = 169/168
In mixed form: 11/168
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/72+30/42 21/72+60/42 21/72+30/84 63/72+30/42 21/72+90/42