Subtract 12/9 from 21/7
1st number: 3 0/7, 2nd number: 1 3/9
21/7 - 12/9 is 5/3.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 7 and 9 is 63
Next, find the equivalent fraction of both fractional numbers with denominator 63 - For the 1st fraction, since 7 × 9 = 63,
21/7 = 21 × 9/7 × 9 = 189/63 - Likewise, for the 2nd fraction, since 9 × 7 = 63,
12/9 = 12 × 7/9 × 7 = 84/63 - Subtract the two like fractions:
189/63 - 84/63 = 189 - 84/63 = 105/63 - After reducing the fraction, the answer is 5/3
- In mixed form: 12/3
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/7-12/9 21/7-24/9 21/14-12/9 21/7-12/18 63/7-12/9 21/7-36/9 21/7-12/27 21/7-60/9 21/35-12/9 21/7-12/45 21/7-84/9 21/49-12/9 21/7-12/63