Add 27/18 and 5/21, Solve 1 9/18 + 5/21 as a fraction

Add 27/18 and 5/21

1^st number: 1 9/18, 2^nd number: 5/21

27/18 + 5/21 is 73/42.

Find the least common denominator or LCM of the two denominators:
LCM of 18 and 21 is 126

Next, find the equivalent fraction of both fractional numbers with denominator 126
For the 1st fraction, since 18 × 7 = 126,
27/18 = 27 × 7/18 × 7 = 189/126
Likewise, for the 2nd fraction, since 21 × 6 = 126,
5/21 = 5 × 6/21 × 6 = 30/126
Add the two like fractions:
189/126 + 30/126 = 189 + 30/126 = 219/126
219/126 simplified gives 73/42
So, 27/18 + 5/21 = 73/42
In mixed form: 131/42

MathStep (Works offline)

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