Answer
Answer is $-10$.
Work Step by Step
$$\text{Solution}$$
Here $A = 01, B = 11.$
Find $A - B = ?$ using 1's complement
$\rightarrow$ First, find 1's complement of $B = 11$
$\rightarrow $ Write out the numbers as if you were subtracting decimals.
$$-\begin{array}{c|c}
01 \\
11 \\
\hline
\end{array}$$
$\rightarrow $ Let's use the 1's Complement Method
$\rightarrow $ 1's complement of a number is obtained by subtracting all bits from $11$
$\rightarrow $ $\text{1's complement of 11 is}$
$$-\begin{array}{c|c}
11 \\
11 \\
\hline
00
\end{array}$$
$\rightarrow $ Now Add this 1's complement of B to A
Note $\rightarrow$ Addition Rules
$0 + 0 = 0$
$0 + 1 = 1$
$1 + 0 = 1$
$1 + 1 = 10$ ("$0$" in the column, carry $1$ to the next bit)
So,
$$+\begin{array}{c|c}
01 \\
00 \\
\hline
01
\end{array}$$
$\rightarrow$ Here there is no carry, the answer is - (1's complement of the sum obtained $01$)
1's complement of $01$ is
$$+\begin{array}{c|c}
11 \\
01 \\
\hline
10
\end{array}$$
so the Answer is $-10$.
