Subtract 21/35 from 21/90
21/90 - 21/35 is -11/30.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 35 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 90 × 7 = 630,
21/90 = 21 × 7/90 × 7 = 147/630 - Likewise, for the 2nd fraction, since 35 × 18 = 630,
21/35 = 21 × 18/35 × 18 = 378/630 - Subtract the two like fractions:
147/630 - 378/630 = 147 - 378/630 = -231/630 - After reducing the fraction, the answer is -11/30
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/90-21/35 21/90-42/35 21/90-21/70 63/90-21/35 21/90-63/35