Subtract 80/7 from 30/90, Solve 30/90

Subtract 80/7 from 30/90

1^st number: 30/90, 2^nd number: 11 3/7

30/90 - 80/7 is -233/21.

Find the least common denominator or LCM of the two denominators:
LCM of 90 and 7 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 90 × 7 = 630,
30/90 = 30 × 7/90 × 7 = 210/630
Likewise, for the 2nd fraction, since 7 × 90 = 630,
80/7 = 80 × 90/7 × 90 = 7200/630
Subtract the two like fractions:
210/630 - 7200/630 = 210 - 7200/630 = -6990/630
After reducing the fraction, the answer is -233/21

MathStep (Works offline)

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