Add 21/12 and 6/42, Solve 1 9/12 + 6/42 as a fraction

Add 21/12 and 6/42

1^st number: 1 9/12, 2^nd number: 6/42

21/12 + 6/42 is 53/28.

Find the least common denominator or LCM of the two denominators:
LCM of 12 and 42 is 84

Next, find the equivalent fraction of both fractional numbers with denominator 84
For the 1st fraction, since 12 × 7 = 84,
21/12 = 21 × 7/12 × 7 = 147/84
Likewise, for the 2nd fraction, since 42 × 2 = 84,
6/42 = 6 × 2/42 × 2 = 12/84
Add the two like fractions:
147/84 + 12/84 = 147 + 12/84 = 159/84
159/84 simplified gives 53/28
So, 21/12 + 6/42 = 53/28
In mixed form: 125/28

MathStep (Works offline)

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