Subtract 54/42 from 18/20
1st number: 18/20, 2nd number: 1 12/42
18/20 - 54/42 is -27/70.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 42 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 20 × 21 = 420,
18/20 = 18 × 21/20 × 21 = 378/420 - Likewise, for the 2nd fraction, since 42 × 10 = 420,
54/42 = 54 × 10/42 × 10 = 540/420 - Subtract the two like fractions:
378/420 - 540/420 = 378 - 540/420 = -162/420 - After reducing the fraction, the answer is -27/70
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/20-54/42 18/40-54/42 18/20-54/84 54/20-54/42 18/60-54/42 90/20-54/42