Subtract 42/12 from 5/21
1st number: 5/21, 2nd number: 3 6/12
5/21 - 42/12 is -137/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 12 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
5/21 = 5 × 4/21 × 4 = 20/84 - Likewise, for the 2nd fraction, since 12 × 7 = 84,
42/12 = 42 × 7/12 × 7 = 294/84 - Subtract the two like fractions:
20/84 - 294/84 = 20 - 294/84 = -274/84 - After reducing the fraction, the answer is -137/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 10/21-42/12 5/21-84/12 5/42-42/12 5/21-42/24 15/21-42/12 5/63-42/12 5/21-42/36 25/21-42/12 5/21-42/60 35/21-42/12 5/21-42/84