Subtract 18/9 from 21/18
1st number: 1 3/18, 2nd number: 2 0/9
21/18 - 18/9 is -5/6.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 9 is 18
Next, find the equivalent fraction of both fractional numbers with denominator 18 - For the 1st fraction, since 18 × 1 = 18,
21/18 = 21 × 1/18 × 1 = 21/18 - Likewise, for the 2nd fraction, since 9 × 2 = 18,
18/9 = 18 × 2/9 × 2 = 36/18 - Subtract the two like fractions:
21/18 - 36/18 = 21 - 36/18 = -15/18 - After reducing the fraction, the answer is -5/6
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/18-18/9 21/18-36/9 21/36-18/9 63/18-18/9 21/18-54/9 21/54-18/9 21/18-18/27 21/18-90/9 21/90-18/9 21/18-18/45 21/18-18/63