Subtract 54/20 from 21/42
1st number: 21/42, 2nd number: 2 14/20
21/42 - 54/20 is -11/5.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 42 × 10 = 420,
21/42 = 21 × 10/42 × 10 = 210/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
54/20 = 54 × 21/20 × 21 = 1134/420 - Subtract the two like fractions:
210/420 - 1134/420 = 210 - 1134/420 = -924/420 - After reducing the fraction, the answer is -11/5
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/84-54/20 21/42-54/40 63/42-54/20 21/42-54/60