Subtract 45/20 from 15/21
1st number: 15/21, 2nd number: 2 5/20
15/21 - 45/20 is -43/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 21 × 20 = 420,
15/21 = 15 × 20/21 × 20 = 300/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
45/20 = 45 × 21/20 × 21 = 945/420 - Subtract the two like fractions:
300/420 - 945/420 = 300 - 945/420 = -645/420 - After reducing the fraction, the answer is -43/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21-45/20 15/21-90/20 15/42-45/20 15/21-45/40 45/21-45/20 15/63-45/20 15/21-45/60 75/21-45/20