Add 72/21 and 6/90, Solve 3 9/21 + 6/90 as a fraction

Add 72/21 and 6/90

1^st number: 3 9/21, 2^nd number: 6/90

72/21 + 6/90 is 367/105.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 90 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 21 × 30 = 630,
72/21 = 72 × 30/21 × 30 = 2160/630
Likewise, for the 2nd fraction, since 90 × 7 = 630,
6/90 = 6 × 7/90 × 7 = 42/630
Add the two like fractions:
2160/630 + 42/630 = 2160 + 42/630 = 2202/630
2202/630 simplified gives 367/105
So, 72/21 + 6/90 = 367/105
In mixed form: 352/105

MathStep (Works offline)

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