Add 42/21 and 18/54, Solve 2 0/21 + 18/54 as a fraction

Add 42/21 and 18/54

1^st number: 2 0/21, 2^nd number: 18/54

42/21 + 18/54 is 7/3.

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

Next, find the equivalent fraction of both fractional numbers with denominator 378
For the 1st fraction, since 21 × 18 = 378,
42/21 = 42 × 18/21 × 18 = 756/378
Likewise, for the 2nd fraction, since 54 × 7 = 378,
18/54 = 18 × 7/54 × 7 = 126/378
Add the two like fractions:
756/378 + 126/378 = 756 + 126/378 = 882/378
882/378 simplified gives 7/3
So, 42/21 + 18/54 = 7/3
In mixed form: 21/3

MathStep (Works offline)

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