Add 30/21 and 45/7, Solve 1 9/21 + 6 3/7 as a fraction

Add 30/21 and 45/7

1^st number: 1 9/21, 2^nd number: 6 3/7

30/21 + 45/7 is 55/7.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 7 is 21

Next, find the equivalent fraction of both fractional numbers with denominator 21
For the 1st fraction, since 21 × 1 = 21,
30/21 = 30 × 1/21 × 1 = 30/21
Likewise, for the 2nd fraction, since 7 × 3 = 21,
45/7 = 45 × 3/7 × 3 = 135/21
Add the two like fractions:
30/21 + 135/21 = 30 + 135/21 = 165/21
165/21 simplified gives 55/7
So, 30/21 + 45/7 = 55/7
In mixed form: 76/7

MathStep (Works offline)

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