Subtract 70/63 from 28/30, Solve 28/30

Subtract 70/63 from 28/30

1^st number: 28/30, 2^nd number: 1 7/63

28/30 - 70/63 is -8/45.

Find the least common denominator or LCM of the two denominators:
LCM of 30 and 63 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 30 × 21 = 630,
28/30 = 28 × 21/30 × 21 = 588/630
Likewise, for the 2nd fraction, since 63 × 10 = 630,
70/63 = 70 × 10/63 × 10 = 700/630
Subtract the two like fractions:
588/630 - 700/630 = 588 - 700/630 = -112/630
After reducing the fraction, the answer is -8/45

MathStep (Works offline)

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