Add 10/20 and 27/21, Solve 10/20 + 1 6/21 as a fraction

Add 10/20 and 27/21

1^st number: 10/20, 2^nd number: 1 6/21

10/20 + 27/21 is 25/14.

Find the least common denominator or LCM of the two denominators:
LCM of 20 and 21 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 20 × 21 = 420,
10/20 = 10 × 21/20 × 21 = 210/420
Likewise, for the 2nd fraction, since 21 × 20 = 420,
27/21 = 27 × 20/21 × 20 = 540/420
Add the two like fractions:
210/420 + 540/420 = 210 + 540/420 = 750/420
750/420 simplified gives 25/14
So, 10/20 + 27/21 = 25/14
In mixed form: 111/14

MathStep (Works offline)

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