Subtract 20/21 from 18/2
1st number: 9 0/2, 2nd number: 20/21
18/2 - 20/21 is 169/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 2 and 21 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 2 × 21 = 42,
18/2 = 18 × 21/2 × 21 = 378/42 - Likewise, for the 2nd fraction, since 21 × 2 = 42,
20/21 = 20 × 2/21 × 2 = 40/42 - Subtract the two like fractions:
378/42 - 40/42 = 378 - 40/42 = 338/42 - After reducing the fraction, the answer is 169/21
- In mixed form: 81/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/2-20/21 18/2-40/21 18/4-20/21 18/2-20/42 54/2-20/21 18/2-60/21 18/6-20/21 18/2-20/63 90/2-20/21 18/10-20/21 18/14-20/21