Add 27/15 and 21/84, Solve 1 12/15 + 21/84 as a fraction

Add 27/15 and 21/84

1^st number: 1 12/15, 2^nd number: 21/84

27/15 + 21/84 is 41/20.

Find the least common denominator or LCM of the two denominators:
LCM of 15 and 84 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 15 × 28 = 420,
27/15 = 27 × 28/15 × 28 = 756/420
Likewise, for the 2nd fraction, since 84 × 5 = 420,
21/84 = 21 × 5/84 × 5 = 105/420
Add the two like fractions:
756/420 + 105/420 = 756 + 105/420 = 861/420
861/420 simplified gives 41/20
So, 27/15 + 21/84 = 41/20
In mixed form: 21/20

MathStep (Works offline)

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