Subtract 90/12 from 12/21
1st number: 12/21, 2nd number: 7 6/12
12/21 - 90/12 is -97/14.
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,
12/21 = 12 × 4/21 × 4 = 48/84 - Likewise, for the 2nd fraction, since 12 × 7 = 84,
90/12 = 90 × 7/12 × 7 = 630/84 - Subtract the two like fractions:
48/84 - 630/84 = 48 - 630/84 = -582/84 - After reducing the fraction, the answer is -97/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/21-90/12 12/42-90/12 12/21-90/24 36/21-90/12 12/63-90/12 12/21-90/36 60/21-90/12 12/21-90/60 84/21-90/12 12/21-90/84