Subtract 3/90 from 21/35
21/35 - 3/90 is 17/30.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 35 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 35 × 18 = 630,
21/35 = 21 × 18/35 × 18 = 378/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
3/90 = 3 × 7/90 × 7 = 21/630 - Subtract the two like fractions:
378/630 - 21/630 = 378 - 21/630 = 357/630 - After reducing the fraction, the answer is 17/30
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/35-3/90 21/35-6/90 21/70-3/90 63/35-3/90 21/35-9/90 21/35-15/90 21/35-21/90