Subtract 12/9 from 20/21
1st number: 20/21, 2nd number: 1 3/9
20/21 - 12/9 is -8/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 9 is 63
Next, find the equivalent fraction of both fractional numbers with denominator 63 - For the 1st fraction, since 21 × 3 = 63,
20/21 = 20 × 3/21 × 3 = 60/63 - Likewise, for the 2nd fraction, since 9 × 7 = 63,
12/9 = 12 × 7/9 × 7 = 84/63 - Subtract the two like fractions:
60/63 - 84/63 = 60 - 84/63 = -24/63 - After reducing the fraction, the answer is -8/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/21-12/9 20/21-24/9 20/42-12/9 20/21-12/18 60/21-12/9 20/21-36/9 20/63-12/9 20/21-12/27 20/21-60/9 20/21-12/45 20/21-84/9 20/21-12/63