Add 45/12 and 72/30, Solve 3 9/12 + 2 12/30 as a fraction

Add 45/12 and 72/30

1^st number: 3 9/12, 2^nd number: 2 12/30

45/12 + 72/30 is 123/20.

Find the least common denominator or LCM of the two denominators:
LCM of 12 and 30 is 60

Next, find the equivalent fraction of both fractional numbers with denominator 60
For the 1st fraction, since 12 × 5 = 60,
45/12 = 45 × 5/12 × 5 = 225/60
Likewise, for the 2nd fraction, since 30 × 2 = 60,
72/30 = 72 × 2/30 × 2 = 144/60
Add the two like fractions:
225/60 + 144/60 = 225 + 144/60 = 369/60
369/60 simplified gives 123/20
So, 45/12 + 72/30 = 123/20
In mixed form: 63/20

MathStep (Works offline)

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