Subtract 30/21 from 42/12
1st number: 3 6/12, 2nd number: 1 9/21
42/12 - 30/21 is 29/14.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 21 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 12 × 7 = 84,
42/12 = 42 × 7/12 × 7 = 294/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
30/21 = 30 × 4/21 × 4 = 120/84 - Subtract the two like fractions:
294/84 - 120/84 = 294 - 120/84 = 174/84 - After reducing the fraction, the answer is 29/14
- In mixed form: 21/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/12-30/21 42/12-60/21 42/24-30/21 42/12-30/42 42/12-90/21 42/36-30/21 42/12-30/63 42/60-30/21 42/84-30/21