Subtract 20/42 from 40/54
40/54 - 20/42 is 50/189.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 54 and 42 is 378
Next, find the equivalent fraction of both fractional numbers with denominator 378 - For the 1st fraction, since 54 × 7 = 378,
40/54 = 40 × 7/54 × 7 = 280/378 - Likewise, for the 2nd fraction, since 42 × 9 = 378,
20/42 = 20 × 9/42 × 9 = 180/378 - Subtract the two like fractions:
280/378 - 180/378 = 280 - 180/378 = 100/378 - After reducing the fraction, the answer is 50/189
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 80/54-20/42 40/54-40/42 40/54-20/84 40/54-60/42