Subtract 40/42 from 1/8
1/8 - 40/42 is -139/168.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 42 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 8 × 21 = 168,
1/8 = 1 × 21/8 × 21 = 21/168 - Likewise, for the 2nd fraction, since 42 × 4 = 168,
40/42 = 40 × 4/42 × 4 = 160/168 - Subtract the two like fractions:
21/168 - 160/168 = 21 - 160/168 = -139/168
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/8-40/42 1/8-80/42 1/16-40/42 1/8-40/84 3/8-40/42 1/24-40/42 5/8-40/42 1/40-40/42 7/8-40/42 1/56-40/42