Subtract 42/84 from 5/81
5/81 - 42/84 is -71/162.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 84 is 2268
Next, find the equivalent fraction of both fractional numbers with denominator 2268 - For the 1st fraction, since 81 × 28 = 2268,
5/81 = 5 × 28/81 × 28 = 140/2268 - Likewise, for the 2nd fraction, since 84 × 27 = 2268,
42/84 = 42 × 27/84 × 27 = 1134/2268 - Subtract the two like fractions:
140/2268 - 1134/2268 = 140 - 1134/2268 = -994/2268 - After reducing the fraction, the answer is -71/162
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 10/81-42/84 15/81-42/84 25/81-42/84 35/81-42/84