Please do the arithmetic operations - no conversion to the decimal system

Given:-
[tex]\begin{gathered} 11101+10001= \\ 111111+1= \\ 101-11= \\ 1000-1= \end{gathered}[/tex]To find the simplified solutions.
So now we simplify,
[tex]\begin{gathered} 11101+10001=21102 \\ 111111+1=111112 \\ 101-11=90 \\ 1000-1=999 \end{gathered}[/tex]So these are the required solutions.