Answers

Subtract 40/84 from 15/81

15/81 - 40/84 is -55/189.

Steps for subtracting fractions

1. 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
2. For the 1st fraction, since 81 × 28 = 2268,
   15/81 = 15 × 28/81 × 28 = 420/2268
3. Likewise, for the 2nd fraction, since 84 × 27 = 2268,
   40/84 = 40 × 27/84 × 27 = 1080/2268
4. Subtract the two like fractions:
   420/2268 - 1080/2268 = 420 - 1080/2268 = -660/2268
5. After reducing the fraction, the answer is -55/189

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