Add 9/21 and 42/27, Solve 9/21 + 1 15/27 as a fraction

Add 9/21 and 42/27

1^st number: 9/21, 2^nd number: 1 15/27

9/21 + 42/27 is 125/63.

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

Next, find the equivalent fraction of both fractional numbers with denominator 189
For the 1st fraction, since 21 × 9 = 189,
9/21 = 9 × 9/21 × 9 = 81/189
Likewise, for the 2nd fraction, since 27 × 7 = 189,
42/27 = 42 × 7/27 × 7 = 294/189
Add the two like fractions:
81/189 + 294/189 = 81 + 294/189 = 375/189
375/189 simplified gives 125/63
So, 9/21 + 42/27 = 125/63
In mixed form: 162/63

MathStep (Works offline)

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