Subtract 8/42 from 1/40
1/40 - 8/42 is -139/840.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 42 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 40 × 21 = 840,
1/40 = 1 × 21/40 × 21 = 21/840 - Likewise, for the 2nd fraction, since 42 × 20 = 840,
8/42 = 8 × 20/42 × 20 = 160/840 - Subtract the two like fractions:
21/840 - 160/840 = 21 - 160/840 = -139/840
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/40-8/42 1/40-16/42 1/80-8/42 1/40-8/84 3/40-8/42 1/40-24/42 5/40-8/42 1/40-40/42 7/40-8/42 1/40-56/42