Add 30/35 and 30/21, Solve 30/35 + 1 9/21 as a fraction

Add 30/35 and 30/21

1^st number: 30/35, 2^nd number: 1 9/21

30/35 + 30/21 is 16/7.

Find the least common denominator or LCM of the two denominators:
LCM of 35 and 21 is 105

Next, find the equivalent fraction of both fractional numbers with denominator 105
For the 1st fraction, since 35 × 3 = 105,
30/35 = 30 × 3/35 × 3 = 90/105
Likewise, for the 2nd fraction, since 21 × 5 = 105,
30/21 = 30 × 5/21 × 5 = 150/105
Add the two like fractions:
90/105 + 150/105 = 90 + 150/105 = 240/105
240/105 simplified gives 16/7
So, 30/35 + 30/21 = 16/7
In mixed form: 22/7

MathStep (Works offline)

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