Exam-style question
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Using 5-bit two’s complement, what is the result of 7 - 3?.
- A.00100
- B.01000
- C.11110
- D.100100
Model answer
What a good answer should say
- 00100
Explanation
Why this works
Represent 7 as 00111. The two’s complement of 3 (00011) is 11101.
Adding gives 00111 + 11101 = 100100. Discard the carry beyond 5 bits, leaving 00100, which is 4.
Common mistake
No common mistake is linked to this question yet.