Add 63/18 and 21/36, Solve 3 9/18 + 21/36 as a fraction

Add 63/18 and 21/36

1^st number: 3 9/18, 2^nd number: 21/36

63/18 + 21/36 is 49/12.

Find the least common denominator or LCM of the two denominators:
LCM of 18 and 36 is 36

Next, find the equivalent fraction of both fractional numbers with denominator 36
For the 1st fraction, since 18 × 2 = 36,
63/18 = 63 × 2/18 × 2 = 126/36
Likewise, for the 2nd fraction, since 36 × 1 = 36,
21/36 = 21 × 1/36 × 1 = 21/36
Add the two like fractions:
126/36 + 21/36 = 126 + 21/36 = 147/36
147/36 simplified gives 49/12
So, 63/18 + 21/36 = 49/12
In mixed form: 41/12

MathStep (Works offline)

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