Subtract 18/28 from 7/81
7/81 - 18/28 is -631/1134.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 28 is 2268
Next, find the equivalent fraction of both fractional numbers with denominator 2268 - For the 1st fraction, since 81 × 28 = 2268,
7/81 = 7 × 28/81 × 28 = 196/2268 - Likewise, for the 2nd fraction, since 28 × 81 = 2268,
18/28 = 18 × 81/28 × 81 = 1458/2268 - Subtract the two like fractions:
196/2268 - 1458/2268 = 196 - 1458/2268 = -1262/2268 - After reducing the fraction, the answer is -631/1134
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 14/81-18/28 7/81-36/28 7/81-18/56 21/81-18/28 7/81-54/28 7/81-18/84 35/81-18/28 7/81-90/28 49/81-18/28