Perform the following operations involving eight$-$bit $2\text{'}$s complement numbers and indicate whether arithmetic overflow occurs. Check your answers by converting to decimal sign$-$andmagnitude representation.

$\backslash$table$[[00110110,01110101,11011111],[+01000101,+11011110,+10111000],[------------------------------------,,]]$

Draw a $4-$bit adder as a block diagram consisting of minimal $1-$bit adders.