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

Add 21/27 and 1/21

21/27 + 1/21 is 52/63.

Find the least common denominator or LCM of the two denominators:
LCM of 27 and 21 is 189

Next, find the equivalent fraction of both fractional numbers with denominator 189
For the 1st fraction, since 27 × 7 = 189,
21/27 = 21 × 7/27 × 7 = 147/189
Likewise, for the 2nd fraction, since 21 × 9 = 189,
1/21 = 1 × 9/21 × 9 = 9/189
Add the two like fractions:
147/189 + 9/189 = 147 + 9/189 = 156/189
156/189 simplified gives 52/63
So, 21/27 + 1/21 = 52/63

MathStep (Works offline)

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