Subtract 20/81 from 4/45
4/45 - 20/81 is -64/405.
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,
4/45 = 4 × 9/45 × 9 = 36/405 - Likewise, for the 2nd fraction, since 81 × 5 = 405,
20/81 = 20 × 5/81 × 5 = 100/405 - Subtract the two like fractions:
36/405 - 100/405 = 36 - 100/405 = -64/405
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 8/45-20/81 4/45-40/81 4/90-20/81 12/45-20/81 4/45-60/81 20/45-20/81 28/45-20/81