Add 30/60 and 70/21, Solve 30/60 + 3 7/21 as a fraction

Add 30/60 and 70/21

1^st number: 30/60, 2^nd number: 3 7/21

30/60 + 70/21 is 23/6.

Find the least common denominator or LCM of the two denominators:
LCM of 60 and 21 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 60 × 7 = 420,
30/60 = 30 × 7/60 × 7 = 210/420
Likewise, for the 2nd fraction, since 21 × 20 = 420,
70/21 = 70 × 20/21 × 20 = 1400/420
Add the two like fractions:
210/420 + 1400/420 = 210 + 1400/420 = 1610/420
1610/420 simplified gives 23/6
So, 30/60 + 70/21 = 23/6
In mixed form: 35/6

MathStep (Works offline)

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