Add 30/4 and 54/21, Solve 7 2/4 + 2 12/21 as a fraction

Add 30/4 and 54/21

1^st number: 7 2/4, 2^nd number: 2 12/21

30/4 + 54/21 is 141/14.

Find the least common denominator or LCM of the two denominators:
LCM of 4 and 21 is 84

Next, find the equivalent fraction of both fractional numbers with denominator 84
For the 1st fraction, since 4 × 21 = 84,
30/4 = 30 × 21/4 × 21 = 630/84
Likewise, for the 2nd fraction, since 21 × 4 = 84,
54/21 = 54 × 4/21 × 4 = 216/84
Add the two like fractions:
630/84 + 216/84 = 630 + 216/84 = 846/84
846/84 simplified gives 141/14
So, 30/4 + 54/21 = 141/14
In mixed form: 101/14

MathStep (Works offline)

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