Add 54/72 and 40/21, Solve 54/72 + 1 19/21 as a fraction

Add 54/72 and 40/21

1^st number: 54/72, 2^nd number: 1 19/21

54/72 + 40/21 is 223/84.

Find the least common denominator or LCM of the two denominators:
LCM of 72 and 21 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 72 × 7 = 504,
54/72 = 54 × 7/72 × 7 = 378/504
Likewise, for the 2nd fraction, since 21 × 24 = 504,
40/21 = 40 × 24/21 × 24 = 960/504
Add the two like fractions:
378/504 + 960/504 = 378 + 960/504 = 1338/504
1338/504 simplified gives 223/84
So, 54/72 + 40/21 = 223/84
In mixed form: 255/84

MathStep (Works offline)

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