Subtract 18/81 from 90/45
1st number: 2 0/45, 2nd number: 18/81
90/45 - 18/81 is 16/9.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 45 and 81 is 405
Next, find the equivalent fraction of both fractional numbers with denominator 405 - For the 1st fraction, since 45 × 9 = 405,
90/45 = 90 × 9/45 × 9 = 810/405 - Likewise, for the 2nd fraction, since 81 × 5 = 405,
18/81 = 18 × 5/81 × 5 = 90/405 - Subtract the two like fractions:
810/405 - 90/405 = 810 - 90/405 = 720/405 - After reducing the fraction, the answer is 16/9
- In mixed form: 17/9
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/45-36/81 90/45-54/81 90/45-90/81