Add 10/21 and 25/8, Solve 10/21 + 3 1/8 as a fraction

Add 10/21 and 25/8

1^st number: 10/21, 2^nd number: 3 1/8

10/21 + 25/8 is 605/168.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 8 is 168

Next, find the equivalent fraction of both fractional numbers with denominator 168
For the 1st fraction, since 21 × 8 = 168,
10/21 = 10 × 8/21 × 8 = 80/168
Likewise, for the 2nd fraction, since 8 × 21 = 168,
25/8 = 25 × 21/8 × 21 = 525/168
Add the two like fractions:
80/168 + 525/168 = 80 + 525/168 = 605/168
So, 10/21 + 25/8 = 605/168
In mixed form: 3101/168

MathStep (Works offline)

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