Subtract 9/21 from 15/42
15/42 - 9/21 is -1/14.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 21 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 42 × 1 = 42,
15/42 = 15 × 1/42 × 1 = 15/42 - Likewise, for the 2nd fraction, since 21 × 2 = 42,
9/21 = 9 × 2/21 × 2 = 18/42 - Subtract the two like fractions:
15/42 - 18/42 = 15 - 18/42 = -3/42 - After reducing the fraction, the answer is -1/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/42-9/21 15/42-18/21 15/84-9/21 15/42-9/42 45/42-9/21 15/42-27/21 15/42-9/63 75/42-9/21 15/42-45/21 15/42-63/21