Add 21/72 and 5/21
21/72 + 5/21 is 89/168.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 21 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 21 × 24 = 504,
5/21 = 5 × 24/21 × 24 = 120/504 - Add the two like fractions:
147/504 + 120/504 = 147 + 120/504 = 267/504 - 267/504 simplified gives 89/168
- So, 21/72 + 5/21 = 89/168
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/72+5/21 21/72+10/21 21/72+5/42 63/72+5/21 21/72+15/21 21/72+5/63 21/72+25/21 21/72+35/21