Add 21/54 and 35/21, Solve 21/54 + 1 14/21 as a fraction

Add 21/54 and 35/21

1^st number: 21/54, 2^nd number: 1 14/21

21/54 + 35/21 is 37/18.

Find the least common denominator or LCM of the two denominators:
LCM of 54 and 21 is 378

Next, find the equivalent fraction of both fractional numbers with denominator 378
For the 1st fraction, since 54 × 7 = 378,
21/54 = 21 × 7/54 × 7 = 147/378
Likewise, for the 2nd fraction, since 21 × 18 = 378,
35/21 = 35 × 18/21 × 18 = 630/378
Add the two like fractions:
147/378 + 630/378 = 147 + 630/378 = 777/378
777/378 simplified gives 37/18
So, 21/54 + 35/21 = 37/18
In mixed form: 21/18

MathStep (Works offline)

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