Subtract 81/90 from 9/12
9/12 - 81/90 is -3/20.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 90 is 180
Next, find the equivalent fraction of both fractional numbers with denominator 180 - For the 1st fraction, since 12 × 15 = 180,
9/12 = 9 × 15/12 × 15 = 135/180 - Likewise, for the 2nd fraction, since 90 × 2 = 180,
81/90 = 81 × 2/90 × 2 = 162/180 - Subtract the two like fractions:
135/180 - 162/180 = 135 - 162/180 = -27/180 - After reducing the fraction, the answer is -3/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 18/12-81/90 9/24-81/90 27/12-81/90 9/36-81/90 45/12-81/90 9/60-81/90 63/12-81/90 9/84-81/90