Add 30/21 and 2/20, Solve 1 9/21 + 2/20 as a fraction

Add 30/21 and 2/20

1^st number: 1 9/21, 2^nd number: 2/20

30/21 + 2/20 is 107/70.

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

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 21 × 20 = 420,
30/21 = 30 × 20/21 × 20 = 600/420
Likewise, for the 2nd fraction, since 20 × 21 = 420,
2/20 = 2 × 21/20 × 21 = 42/420
Add the two like fractions:
600/420 + 42/420 = 600 + 42/420 = 642/420
642/420 simplified gives 107/70
So, 30/21 + 2/20 = 107/70
In mixed form: 137/70

MathStep (Works offline)

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