Add 35/20 and 40/21, Solve 1 15/20 + 1 19/21 as a fraction

Add 35/20 and 40/21

1^st number: 1 15/20, 2^nd number: 1 19/21

35/20 + 40/21 is 307/84.

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,
35/20 = 35 × 21/20 × 21 = 735/420
Likewise, for the 2nd fraction, since 21 × 20 = 420,
40/21 = 40 × 20/21 × 20 = 800/420
Add the two like fractions:
735/420 + 800/420 = 735 + 800/420 = 1535/420
1535/420 simplified gives 307/84
So, 35/20 + 40/21 = 307/84
In mixed form: 355/84

MathStep (Works offline)

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