Subtract 4/45 from 1/21
1/21 - 4/45 is -13/315.
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,
1/21 = 1 × 15/21 × 15 = 15/315 - Likewise, for the 2nd fraction, since 45 × 7 = 315,
4/45 = 4 × 7/45 × 7 = 28/315 - Subtract the two like fractions:
15/315 - 28/315 = 15 - 28/315 = -13/315
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/21-4/45 1/21-8/45 1/42-4/45 1/21-4/90 3/21-4/45 1/21-12/45 1/63-4/45 5/21-4/45 1/21-20/45 7/21-4/45 1/21-28/45