Subtract 4/20 from 20/42
20/42 - 4/20 is 29/105.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 42 × 10 = 420,
20/42 = 20 × 10/42 × 10 = 200/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
4/20 = 4 × 21/20 × 21 = 84/420 - Subtract the two like fractions:
200/420 - 84/420 = 200 - 84/420 = 116/420 - After reducing the fraction, the answer is 29/105
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/42-4/20 20/42-8/20 20/84-4/20 20/42-4/40 60/42-4/20 20/42-12/20 20/42-4/60 20/42-28/20