Use the 1's complement method to subtract the following binary numbers.
$\begin{array} { r }
10010\
1010100\
\hline
\end{array}$
A) -1010101
B) -1010011
C) -1001101
D) -1000010
E) -1000111

Question

Use the 1's complement method to subtract the following binary numbers. 
$\begin{array} { r } 
10010\
1010100\
\hline
\end{array}$
A) -1010101
B) -1010011
C) -1001101
D) -1000010
E) -1000111

Quizplus · Accepted Answer

To subtract using 1's complement method, we need to take the 1's complement of the subtrahend (the second number) and add it to the minuend (the first number), including the carry (if any) from the previous position. 
10010 = (00010010)$_2$
1010100 = (01111100)$_2$
Taking the 1's complement of the subtrahend:
(10000011)$_2$
Adding it to the minuend, including the carry:
  00010010
+ 10000011
__________
  10010101
Since the leftmost digit is 1, it represents a negative number in 1's complement form. Taking the 1's complement of this result gives us:
(01101010)$_2$ 
This is equivalent to -1000010 in signed binary, which is the answer D.

Use the 1's Complement Method to Subtract the Following Binary 100101010100\begin{array} { r } 10010\\1010100\\\hline\end{array}100101010100​​

Use the 1's Complement Method to Subtract the Following Binary $\begin{array} { r } 10010\\1010100\\\hline\end{array}$