Subtract 8/21 from 4/90
4/90 - 8/21 is -106/315.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 21 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 90 × 7 = 630,
4/90 = 4 × 7/90 × 7 = 28/630 - Likewise, for the 2nd fraction, since 21 × 30 = 630,
8/21 = 8 × 30/21 × 30 = 240/630 - Subtract the two like fractions:
28/630 - 240/630 = 28 - 240/630 = -212/630 - After reducing the fraction, the answer is -106/315
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 8/90-8/21 4/90-16/21 4/90-8/42 12/90-8/21 4/90-24/21 4/90-8/63 20/90-8/21 4/90-40/21 28/90-8/21 4/90-56/21