Add 81/72 and 4/21
1st number: 1 9/72, 2nd number: 4/21
81/72 + 4/21 is 221/168.
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,
81/72 = 81 × 7/72 × 7 = 567/504 - Likewise, for the 2nd fraction, since 21 × 24 = 504,
4/21 = 4 × 24/21 × 24 = 96/504 - Add the two like fractions:
567/504 + 96/504 = 567 + 96/504 = 663/504 - 663/504 simplified gives 221/168
- So, 81/72 + 4/21 = 221/168
In mixed form: 153/168
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 81/72+8/21 81/72+4/42 81/72+12/21 81/72+4/63 81/72+20/21 81/72+28/21