Add 27/36 and 80/21, Solve 27/36 + 3 17/21 as a fraction

Add 27/36 and 80/21

1^st number: 27/36, 2^nd number: 3 17/21

27/36 + 80/21 is 383/84.

Find the least common denominator or LCM of the two denominators:
LCM of 36 and 21 is 252

Next, find the equivalent fraction of both fractional numbers with denominator 252
For the 1st fraction, since 36 × 7 = 252,
27/36 = 27 × 7/36 × 7 = 189/252
Likewise, for the 2nd fraction, since 21 × 12 = 252,
80/21 = 80 × 12/21 × 12 = 960/252
Add the two like fractions:
189/252 + 960/252 = 189 + 960/252 = 1149/252
1149/252 simplified gives 383/84
So, 27/36 + 80/21 = 383/84
In mixed form: 447/84

MathStep (Works offline)

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