Subtract 70/81 from 18/90
18/90 - 70/81 is -269/405.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 81 is 810
Next, find the equivalent fraction of both fractional numbers with denominator 810 - For the 1st fraction, since 90 × 9 = 810,
18/90 = 18 × 9/90 × 9 = 162/810 - Likewise, for the 2nd fraction, since 81 × 10 = 810,
70/81 = 70 × 10/81 × 10 = 700/810 - Subtract the two like fractions:
162/810 - 700/810 = 162 - 700/810 = -538/810 - After reducing the fraction, the answer is -269/405
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/90-70/81 54/90-70/81