Subtract 3/9 from 18/21
18/21 - 3/9 is 11/21.
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,
18/21 = 18 × 3/21 × 3 = 54/63 - Likewise, for the 2nd fraction, since 9 × 7 = 63,
3/9 = 3 × 7/9 × 7 = 21/63 - Subtract the two like fractions:
54/63 - 21/63 = 54 - 21/63 = 33/63 - After reducing the fraction, the answer is 11/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/21-3/9 18/21-6/9 18/42-3/9 18/21-3/18 54/21-3/9 18/63-3/9 18/21-3/27 90/21-3/9 18/21-15/9 18/21-3/45 18/21-21/9 18/21-3/63