Add 36/21 and 21/80, Solve 1 15/21 + 21/80 as a fraction

Add 36/21 and 21/80

1^st number: 1 15/21, 2^nd number: 21/80

36/21 + 21/80 is 1107/560.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 80 is 1680

Next, find the equivalent fraction of both fractional numbers with denominator 1680
For the 1st fraction, since 21 × 80 = 1680,
36/21 = 36 × 80/21 × 80 = 2880/1680
Likewise, for the 2nd fraction, since 80 × 21 = 1680,
21/80 = 21 × 21/80 × 21 = 441/1680
Add the two like fractions:
2880/1680 + 441/1680 = 2880 + 441/1680 = 3321/1680
3321/1680 simplified gives 1107/560
So, 36/21 + 21/80 = 1107/560
In mixed form: 1547/560

MathStep (Works offline)

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