Subtract 24/12 from 21/42
1st number: 21/42, 2nd number: 2 0/12
21/42 - 24/12 is -3/2.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 12 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 42 × 2 = 84,
21/42 = 21 × 2/42 × 2 = 42/84 - Likewise, for the 2nd fraction, since 12 × 7 = 84,
24/12 = 24 × 7/12 × 7 = 168/84 - Subtract the two like fractions:
42/84 - 168/84 = 42 - 168/84 = -126/84 - After reducing the fraction, the answer is -3/2
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/42-48/12 21/84-24/12 63/42-24/12 21/42-72/12 21/42-24/36 21/42-24/60 21/42-24/84