Subtract 80/81 from 4/40
4/40 - 80/81 is -719/810.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 81 is 3240
Next, find the equivalent fraction of both fractional numbers with denominator 3240 - For the 1st fraction, since 40 × 81 = 3240,
4/40 = 4 × 81/40 × 81 = 324/3240 - Likewise, for the 2nd fraction, since 81 × 40 = 3240,
80/81 = 80 × 40/81 × 40 = 3200/3240 - Subtract the two like fractions:
324/3240 - 3200/3240 = 324 - 3200/3240 = -2876/3240 - After reducing the fraction, the answer is -719/810
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 8/40-80/81 4/80-80/81 12/40-80/81 20/40-80/81 28/40-80/81