Topic: Digital Electronics
The two numbers represented in signed 2's complement form are $P=11101101$ and $Q=11100110$. If Q is subtracted from P, the value obtained in signed 2's complement is
- A. 1000001111
- B. 00000111
- C. 11111001
- D. 111111001
Answer: B. 00000111
Explanation: To perform $P - Q$, we take the 2's complement of the subtrahend $Q$ and add it to the minuend $P$.
$P = 11101101$
$Q = 11100110$, so the 2's complement of $Q = 00011010$.
Adding them: $11101101 + 00011010 = 1 00000111$.
Since there is a carry out of the sign bit, the answer is positive, and the carry is neglected. The result is $00000111$.