Subtract 20/7 from 18/42
1st number: 18/42, 2nd number: 2 6/7
18/42 - 20/7 is -17/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 7 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 42 × 1 = 42,
18/42 = 18 × 1/42 × 1 = 18/42 - Likewise, for the 2nd fraction, since 7 × 6 = 42,
20/7 = 20 × 6/7 × 6 = 120/42 - Subtract the two like fractions:
18/42 - 120/42 = 18 - 120/42 = -102/42 - After reducing the fraction, the answer is -17/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/42-20/7 18/42-40/7 18/84-20/7 18/42-20/14 54/42-20/7 18/42-60/7 18/42-20/21 90/42-20/7 18/42-20/35 18/42-20/49