Subtract 10/5 from 21/81
1st number: 21/81, 2nd number: 2 0/5
21/81 - 10/5 is -47/27.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 5 is 405
Next, find the equivalent fraction of both fractional numbers with denominator 405 - For the 1st fraction, since 81 × 5 = 405,
21/81 = 21 × 5/81 × 5 = 105/405 - Likewise, for the 2nd fraction, since 5 × 81 = 405,
10/5 = 10 × 81/5 × 81 = 810/405 - Subtract the two like fractions:
105/405 - 810/405 = 105 - 810/405 = -705/405 - After reducing the fraction, the answer is -47/27
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/81-10/5 21/81-20/5 63/81-10/5 21/81-30/5 21/81-10/15 21/81-50/5 21/81-10/25 21/81-70/5 21/81-10/35