Subtract 98/21 from 21/18, Solve 1 3/18

Subtract 98/21 from 21/18

1^st number: 1 3/18, 2^nd number: 4 14/21

21/18 - 98/21 is -7/2.

Find the least common denominator or LCM of the two denominators:
LCM of 18 and 21 is 126

Next, find the equivalent fraction of both fractional numbers with denominator 126
For the 1st fraction, since 18 × 7 = 126,
21/18 = 21 × 7/18 × 7 = 147/126
Likewise, for the 2nd fraction, since 21 × 6 = 126,
98/21 = 98 × 6/21 × 6 = 588/126
Subtract the two like fractions:
147/126 - 588/126 = 147 - 588/126 = -441/126
After reducing the fraction, the answer is -7/2

MathStep (Works offline)

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