Add 20/72 and 40/21, Solve 20/72 + 1 19/21 as a fraction

Add 20/72 and 40/21

1^st number: 20/72, 2^nd number: 1 19/21

20/72 + 40/21 is 275/126.

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,
20/72 = 20 × 7/72 × 7 = 140/504
Likewise, for the 2nd fraction, since 21 × 24 = 504,
40/21 = 40 × 24/21 × 24 = 960/504
Add the two like fractions:
140/504 + 960/504 = 140 + 960/504 = 1100/504
1100/504 simplified gives 275/126
So, 20/72 + 40/21 = 275/126
In mixed form: 223/126

MathStep (Works offline)

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