Add 81/72 and 40/42, Solve 1 9/72 + 40/42 as a fraction

Add 81/72 and 40/42

1^st number: 1 9/72, 2^nd number: 40/42

81/72 + 40/42 is 349/168.

Find the least common denominator or LCM of the two denominators:
LCM of 72 and 42 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 72 × 7 = 504,
81/72 = 81 × 7/72 × 7 = 567/504
Likewise, for the 2nd fraction, since 42 × 12 = 504,
40/42 = 40 × 12/42 × 12 = 480/504
Add the two like fractions:
567/504 + 480/504 = 567 + 480/504 = 1047/504
1047/504 simplified gives 349/168
So, 81/72 + 40/42 = 349/168
In mixed form: 213/168

MathStep (Works offline)

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