Subtract 21/90 from 24/81
24/81 - 21/90 is 17/270.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 90 is 810
Next, find the equivalent fraction of both fractional numbers with denominator 810 - For the 1st fraction, since 81 × 10 = 810,
24/81 = 24 × 10/81 × 10 = 240/810 - Likewise, for the 2nd fraction, since 90 × 9 = 810,
21/90 = 21 × 9/90 × 9 = 189/810 - Subtract the two like fractions:
240/810 - 189/810 = 240 - 189/810 = 51/810 - After reducing the fraction, the answer is 17/270
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 48/81-21/90 24/81-42/90 72/81-21/90 24/81-63/90