Add 12/56 and 8/21, Solve 12/56 + 8/21 as a fraction

Add 12/56 and 8/21

12/56 + 8/21 is 25/42.

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,
12/56 = 12 × 3/56 × 3 = 36/168
Likewise, for the 2nd fraction, since 21 × 8 = 168,
8/21 = 8 × 8/21 × 8 = 64/168
Add the two like fractions:
36/168 + 64/168 = 36 + 64/168 = 100/168
100/168 simplified gives 25/42
So, 12/56 + 8/21 = 25/42

MathStep (Works offline)

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