Add 27/15 and 15/21, Solve 1 12/15 + 15/21 as a fraction

Add 27/15 and 15/21

1^st number: 1 12/15, 2^nd number: 15/21

27/15 + 15/21 is 88/35.

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

Next, find the equivalent fraction of both fractional numbers with denominator 105
For the 1st fraction, since 15 × 7 = 105,
27/15 = 27 × 7/15 × 7 = 189/105
Likewise, for the 2nd fraction, since 21 × 5 = 105,
15/21 = 15 × 5/21 × 5 = 75/105
Add the two like fractions:
189/105 + 75/105 = 189 + 75/105 = 264/105
264/105 simplified gives 88/35
So, 27/15 + 15/21 = 88/35
In mixed form: 218/35

MathStep (Works offline)

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