Add 28/56 and 20/21, Solve 28/56 + 20/21 as a fraction

Add 28/56 and 20/21

28/56 + 20/21 is 61/42.

Find the least common denominator or LCM of the two denominators:
LCM of 56 and 21 is 168

Next, find the equivalent fraction of both fractional numbers with denominator 168
For the 1st fraction, since 56 × 3 = 168,
28/56 = 28 × 3/56 × 3 = 84/168
Likewise, for the 2nd fraction, since 21 × 8 = 168,
20/21 = 20 × 8/21 × 8 = 160/168
Add the two like fractions:
84/168 + 160/168 = 84 + 160/168 = 244/168
244/168 simplified gives 61/42
So, 28/56 + 20/21 = 61/42
In mixed form: 119/42

MathStep (Works offline)

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