Add 21/56 and 24/21, Solve 21/56 + 1 3/21 as a fraction

Add 21/56 and 24/21

1^st number: 21/56, 2^nd number: 1 3/21

21/56 + 24/21 is 85/56.

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,
21/56 = 21 × 3/56 × 3 = 63/168
Likewise, for the 2nd fraction, since 21 × 8 = 168,
24/21 = 24 × 8/21 × 8 = 192/168
Add the two like fractions:
63/168 + 192/168 = 63 + 192/168 = 255/168
255/168 simplified gives 85/56
So, 21/56 + 24/21 = 85/56
In mixed form: 129/56

MathStep (Works offline)

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