Subtract 10/21 from 3/9
3/9 - 10/21 is -1/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 9 and 21 is 63
Next, find the equivalent fraction of both fractional numbers with denominator 63 - For the 1st fraction, since 9 × 7 = 63,
3/9 = 3 × 7/9 × 7 = 21/63 - Likewise, for the 2nd fraction, since 21 × 3 = 63,
10/21 = 10 × 3/21 × 3 = 30/63 - Subtract the two like fractions:
21/63 - 30/63 = 21 - 30/63 = -9/63 - After reducing the fraction, the answer is -1/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/9-10/21 3/9-20/21 3/18-10/21 3/9-10/42 3/9-30/21 3/27-10/21 3/9-10/63 15/9-10/21 3/9-50/21 3/45-10/21 21/9-10/21 3/9-70/21 3/63-10/21