Example 17 Find $(11101)_{2}-(1011)_{2}=$ ?
Solve: First, find the complement of $(1011)_{2}$, which is $(0101)_{2}=(101)_{2}$. Then add this complement to the minuend (11101) to get

Then subtract $(10000)_{2}$ to obtain the answer of this subtraction:
$$\begin{array}{l}
\left(\begin{array}{lllll}
1 & 1 & 1 & 0 & 1
\end{array}\right)_{2} \\
\frac{+\quad(101)_{2}}{(100010)_{2}},
\end{array}$$
$$\begin{array}{l}
(100010)_{2} \\
-\frac{(100000)_{2}}{(10010)_{2}} \text {. }
\end{array}$$