Subtract 12/9 from 3/21
1st number: 3/21, 2nd number: 1 3/9
3/21 - 12/9 is -25/21.
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,
3/21 = 3 × 3/21 × 3 = 9/63 - Likewise, for the 2nd fraction, since 9 × 7 = 63,
12/9 = 12 × 7/9 × 7 = 84/63 - Subtract the two like fractions:
9/63 - 84/63 = 9 - 84/63 = -75/63 - After reducing the fraction, the answer is -25/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/21-12/9 3/21-24/9 3/42-12/9 3/21-12/18 9/21-12/9 3/21-36/9 3/63-12/9 3/21-12/27 15/21-12/9 3/21-60/9 3/21-12/45 3/21-84/9 3/21-12/63