Add 36/21 and 63/42, Solve 1 15/21 + 1 21/42 as a fraction

Add 36/21 and 63/42

1^st number: 1 15/21, 2^nd number: 1 21/42

36/21 + 63/42 is 45/14.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 42 is 42

Next, find the equivalent fraction of both fractional numbers with denominator 42
For the 1st fraction, since 21 × 2 = 42,
36/21 = 36 × 2/21 × 2 = 72/42
Likewise, for the 2nd fraction, since 42 × 1 = 42,
63/42 = 63 × 1/42 × 1 = 63/42
Add the two like fractions:
72/42 + 63/42 = 72 + 63/42 = 135/42
135/42 simplified gives 45/14
So, 36/21 + 63/42 = 45/14
In mixed form: 33/14

MathStep (Works offline)

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