Add 72/21 and 56/36, Solve 3 9/21 + 1 20/36 as a fraction

Add 72/21 and 56/36

1^st number: 3 9/21, 2^nd number: 1 20/36

72/21 + 56/36 is 314/63.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 36 is 252

Next, find the equivalent fraction of both fractional numbers with denominator 252
For the 1st fraction, since 21 × 12 = 252,
72/21 = 72 × 12/21 × 12 = 864/252
Likewise, for the 2nd fraction, since 36 × 7 = 252,
56/36 = 56 × 7/36 × 7 = 392/252
Add the two like fractions:
864/252 + 392/252 = 864 + 392/252 = 1256/252
1256/252 simplified gives 314/63
So, 72/21 + 56/36 = 314/63
In mixed form: 462/63

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad