Subtract 20/42 from 18/36
18/36 - 20/42 is 1/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 36 and 42 is 252
Next, find the equivalent fraction of both fractional numbers with denominator 252 - For the 1st fraction, since 36 × 7 = 252,
18/36 = 18 × 7/36 × 7 = 126/252 - Likewise, for the 2nd fraction, since 42 × 6 = 252,
20/42 = 20 × 6/42 × 6 = 120/252 - Subtract the two like fractions:
126/252 - 120/252 = 126 - 120/252 = 6/252 - After reducing the fraction, the answer is 1/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 18/36-40/42 18/72-20/42 18/36-20/84 54/36-20/42 18/36-60/42 90/36-20/42