Add 25/21 and 10/15, Solve 1 4/21 + 10/15 as a fraction

Add 25/21 and 10/15

1^st number: 1 4/21, 2^nd number: 10/15

25/21 + 10/15 is 13/7.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 15 is 105

Next, find the equivalent fraction of both fractional numbers with denominator 105
For the 1st fraction, since 21 × 5 = 105,
25/21 = 25 × 5/21 × 5 = 125/105
Likewise, for the 2nd fraction, since 15 × 7 = 105,
10/15 = 10 × 7/15 × 7 = 70/105
Add the two like fractions:
125/105 + 70/105 = 125 + 70/105 = 195/105
195/105 simplified gives 13/7
So, 25/21 + 10/15 = 13/7
In mixed form: 16/7

MathStep (Works offline)

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