Add 72/80 and 21/28
72/80 + 21/28 is 33/20.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 80 and 28 is 560
Next, find the equivalent fraction of both fractional numbers with denominator 560 - For the 1st fraction, since 80 × 7 = 560,
72/80 = 72 × 7/80 × 7 = 504/560 - Likewise, for the 2nd fraction, since 28 × 20 = 560,
21/28 = 21 × 20/28 × 20 = 420/560 - Add the two like fractions:
504/560 + 420/560 = 504 + 420/560 = 924/560 - 924/560 simplified gives 33/20
- So, 72/80 + 21/28 = 33/20
In mixed form: 113/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/80+42/28 72/80+21/56 72/80+63/28 72/80+21/84