Subtract 90/21 from 4/5
1st number: 4/5, 2nd number: 4 6/21
4/5 - 90/21 is -122/35.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 5 and 21 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 5 × 21 = 105,
4/5 = 4 × 21/5 × 21 = 84/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
90/21 = 90 × 5/21 × 5 = 450/105 - Subtract the two like fractions:
84/105 - 450/105 = 84 - 450/105 = -366/105 - After reducing the fraction, the answer is -122/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 8/5-90/21 4/10-90/21 4/5-90/42 12/5-90/21 4/15-90/21 4/5-90/63 20/5-90/21 4/25-90/21 28/5-90/21 4/35-90/21