Subtract 9/20 from 5/42
5/42 - 9/20 is -139/420.
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,
5/42 = 5 × 10/42 × 10 = 50/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
9/20 = 9 × 21/20 × 21 = 189/420 - Subtract the two like fractions:
50/420 - 189/420 = 50 - 189/420 = -139/420
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 10/42-9/20 5/42-18/20 5/84-9/20 5/42-9/40 15/42-9/20 5/42-27/20 5/42-9/60 25/42-9/20 5/42-45/20 35/42-9/20 5/42-63/20