Subtract 20/24 from 9/42
9/42 - 20/24 is -13/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 24 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 42 × 4 = 168,
9/42 = 9 × 4/42 × 4 = 36/168 - Likewise, for the 2nd fraction, since 24 × 7 = 168,
20/24 = 20 × 7/24 × 7 = 140/168 - Subtract the two like fractions:
36/168 - 140/168 = 36 - 140/168 = -104/168 - After reducing the fraction, the answer is -13/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 18/42-20/24 9/42-40/24 9/84-20/24 9/42-20/48 27/42-20/24 9/42-60/24 9/42-20/72 45/42-20/24 63/42-20/24