Subtract 8/45 from 20/21
20/21 - 8/45 is 244/315.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 45 is 315
Next, find the equivalent fraction of both fractional numbers with denominator 315 - For the 1st fraction, since 21 × 15 = 315,
20/21 = 20 × 15/21 × 15 = 300/315 - Likewise, for the 2nd fraction, since 45 × 7 = 315,
8/45 = 8 × 7/45 × 7 = 56/315 - Subtract the two like fractions:
300/315 - 56/315 = 300 - 56/315 = 244/315
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/21-8/45 20/21-16/45 20/42-8/45 20/21-8/90 60/21-8/45 20/21-24/45 20/63-8/45 20/21-40/45 20/21-56/45