Subtract 21/18 from 18/70
1st number: 18/70, 2nd number: 1 3/18
18/70 - 21/18 is -191/210.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 18 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 70 × 9 = 630,
18/70 = 18 × 9/70 × 9 = 162/630 - Likewise, for the 2nd fraction, since 18 × 35 = 630,
21/18 = 21 × 35/18 × 35 = 735/630 - Subtract the two like fractions:
162/630 - 735/630 = 162 - 735/630 = -573/630 - After reducing the fraction, the answer is -191/210
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/70-21/18 18/70-42/18 18/70-21/36 54/70-21/18 18/70-63/18 18/70-21/54 90/70-21/18 18/70-21/90