Add 27/21 and 9/15, Solve 1 6/21 + 9/15 as a fraction

Add 27/21 and 9/15

1^st number: 1 6/21, 2^nd number: 9/15

27/21 + 9/15 is 66/35.

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,
27/21 = 27 × 5/21 × 5 = 135/105
Likewise, for the 2nd fraction, since 15 × 7 = 105,
9/15 = 9 × 7/15 × 7 = 63/105
Add the two like fractions:
135/105 + 63/105 = 135 + 63/105 = 198/105
198/105 simplified gives 66/35
So, 27/21 + 9/15 = 66/35
In mixed form: 131/35

MathStep (Works offline)

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