Subtract 7/9 from 90/20, Solve 4 10/20

Subtract 7/9 from 90/20

1^st number: 4 10/20, 2^nd number: 7/9

90/20 - 7/9 is 67/18.

Find the least common denominator or LCM of the two denominators:
LCM of 20 and 9 is 180

Next, find the equivalent fraction of both fractional numbers with denominator 180
For the 1st fraction, since 20 × 9 = 180,
90/20 = 90 × 9/20 × 9 = 810/180
Likewise, for the 2nd fraction, since 9 × 20 = 180,
7/9 = 7 × 20/9 × 20 = 140/180
Subtract the two like fractions:
810/180 - 140/180 = 810 - 140/180 = 670/180
After reducing the fraction, the answer is 67/18
In mixed form: 313/18

MathStep (Works offline)

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