Subtract 20/42 from 8/20
8/20 - 20/42 is -8/105.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 42 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 20 × 21 = 420,
8/20 = 8 × 21/20 × 21 = 168/420 - Likewise, for the 2nd fraction, since 42 × 10 = 420,
20/42 = 20 × 10/42 × 10 = 200/420 - Subtract the two like fractions:
168/420 - 200/420 = 168 - 200/420 = -32/420 - After reducing the fraction, the answer is -8/105
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 16/20-20/42 8/20-40/42 8/40-20/42 8/20-20/84 24/20-20/42 8/20-60/42 8/60-20/42 40/20-20/42 56/20-20/42