Add 30/70 and 21/18, Solve 30/70 + 1 3/18 as a fraction

Add 30/70 and 21/18

1^st number: 30/70, 2^nd number: 1 3/18

30/70 + 21/18 is 67/42.

Find the least common denominator or LCM of the two denominators:
LCM of 70 and 18 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 70 × 9 = 630,
30/70 = 30 × 9/70 × 9 = 270/630
Likewise, for the 2nd fraction, since 18 × 35 = 630,
21/18 = 21 × 35/18 × 35 = 735/630
Add the two like fractions:
270/630 + 735/630 = 270 + 735/630 = 1005/630
1005/630 simplified gives 67/42
So, 30/70 + 21/18 = 67/42
In mixed form: 125/42

MathStep (Works offline)

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