Add 42/27 and 63/21, Solve 1 15/27 + 3 0/21 as a fraction

Add 42/27 and 63/21

1^st number: 1 15/27, 2^nd number: 3 0/21

42/27 + 63/21 is 41/9.

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,
42/27 = 42 × 7/27 × 7 = 294/189
Likewise, for the 2nd fraction, since 21 × 9 = 189,
63/21 = 63 × 9/21 × 9 = 567/189
Add the two like fractions:
294/189 + 567/189 = 294 + 567/189 = 861/189
861/189 simplified gives 41/9
So, 42/27 + 63/21 = 41/9
In mixed form: 45/9

MathStep (Works offline)

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