Add 27/21 and 54/63, Solve 1 6/21 + 54/63 as a fraction

Add 27/21 and 54/63

1^st number: 1 6/21, 2^nd number: 54/63

27/21 + 54/63 is 15/7.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 63 is 63

Next, find the equivalent fraction of both fractional numbers with denominator 63
For the 1st fraction, since 21 × 3 = 63,
27/21 = 27 × 3/21 × 3 = 81/63
Likewise, for the 2nd fraction, since 63 × 1 = 63,
54/63 = 54 × 1/63 × 1 = 54/63
Add the two like fractions:
81/63 + 54/63 = 81 + 54/63 = 135/63
135/63 simplified gives 15/7
So, 27/21 + 54/63 = 15/7
In mixed form: 21/7

MathStep (Works offline)

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