Subtract 18/81 from 72/84
72/84 - 18/81 is 40/63.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 81 is 2268
Next, find the equivalent fraction of both fractional numbers with denominator 2268 - For the 1st fraction, since 84 × 27 = 2268,
72/84 = 72 × 27/84 × 27 = 1944/2268 - Likewise, for the 2nd fraction, since 81 × 28 = 2268,
18/81 = 18 × 28/81 × 28 = 504/2268 - Subtract the two like fractions:
1944/2268 - 504/2268 = 1944 - 504/2268 = 1440/2268 - After reducing the fraction, the answer is 40/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/84-36/81 72/84-54/81 72/84-90/81