Subtract 4/42 from 21/12
1st number: 1 9/12, 2nd number: 4/42
21/12 - 4/42 is 139/84.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 42 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 12 × 7 = 84,
21/12 = 21 × 7/12 × 7 = 147/84 - Likewise, for the 2nd fraction, since 42 × 2 = 84,
4/42 = 4 × 2/42 × 2 = 8/84 - Subtract the two like fractions:
147/84 - 8/84 = 147 - 8/84 = 139/84 - In mixed form: 155/84
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/12-4/42 21/12-8/42 21/24-4/42 21/12-4/84 63/12-4/42 21/12-12/42 21/36-4/42 21/12-20/42 21/60-4/42 21/12-28/42 21/84-4/42