Subtract 18/84 from 1/42
1/42 - 18/84 is -4/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 84 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 42 × 2 = 84,
1/42 = 1 × 2/42 × 2 = 2/84 - Likewise, for the 2nd fraction, since 84 × 1 = 84,
18/84 = 18 × 1/84 × 1 = 18/84 - Subtract the two like fractions:
2/84 - 18/84 = 2 - 18/84 = -16/84 - After reducing the fraction, the answer is -4/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/42-18/84 1/42-36/84 1/84-18/84 3/42-18/84 1/42-54/84 5/42-18/84 1/42-90/84 7/42-18/84