Subtract 25/40 from 20/21
20/21 - 25/40 is 55/168.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 21 × 40 = 840,
20/21 = 20 × 40/21 × 40 = 800/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
25/40 = 25 × 21/40 × 21 = 525/840 - Subtract the two like fractions:
800/840 - 525/840 = 800 - 525/840 = 275/840 - After reducing the fraction, the answer is 55/168
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/21-25/40 20/21-50/40 20/42-25/40 20/21-25/80 60/21-25/40 20/21-75/40 20/63-25/40