Subtract 8/7 from 12/21
1st number: 12/21, 2nd number: 1 1/7
12/21 - 8/7 is -4/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 7 is 21
Next, find the equivalent fraction of both fractional numbers with denominator 21 - For the 1st fraction, since 21 × 1 = 21,
12/21 = 12 × 1/21 × 1 = 12/21 - Likewise, for the 2nd fraction, since 7 × 3 = 21,
8/7 = 8 × 3/7 × 3 = 24/21 - Subtract the two like fractions:
12/21 - 24/21 = 12 - 24/21 = -12/21 - After reducing the fraction, the answer is -4/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/21-8/7 12/21-16/7 12/42-8/7 12/21-8/14 36/21-8/7 12/21-24/7 12/63-8/7 12/21-8/21 60/21-8/7 12/21-40/7 12/21-8/35 84/21-8/7 12/21-56/7 12/21-8/49