Add 63/4 and 45/12, Solve 15 3/4 + 3 9/12 as a fraction

Add 63/4 and 45/12

1^st number: 15 3/4, 2^nd number: 3 9/12

63/4 + 45/12 is 39/2.

Find the least common denominator or LCM of the two denominators:
LCM of 4 and 12 is 12

Next, find the equivalent fraction of both fractional numbers with denominator 12
For the 1st fraction, since 4 × 3 = 12,
63/4 = 63 × 3/4 × 3 = 189/12
Likewise, for the 2nd fraction, since 12 × 1 = 12,
45/12 = 45 × 1/12 × 1 = 45/12
Add the two like fractions:
189/12 + 45/12 = 189 + 45/12 = 234/12
234/12 simplified gives 39/2
So, 63/4 + 45/12 = 39/2
In mixed form: 191/2

MathStep (Works offline)

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