Subtract 81/42 from 12/28
1st number: 12/28, 2nd number: 1 39/42
12/28 - 81/42 is -3/2.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 42 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 28 × 3 = 84,
12/28 = 12 × 3/28 × 3 = 36/84 - Likewise, for the 2nd fraction, since 42 × 2 = 84,
81/42 = 81 × 2/42 × 2 = 162/84 - Subtract the two like fractions:
36/84 - 162/84 = 36 - 162/84 = -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: 24/28-81/42 12/56-81/42 12/28-81/84 36/28-81/42 12/84-81/42 60/28-81/42 84/28-81/42