Need Help plsDesign the following digital circuits using AND, OR and NOT gates:
a) A binary addtition- substraction circuit that adds or subtracts two 4 bit binary numbers. The circuit has a selection bit that controls whether addition or substraction is to be performed.
b) Draw a combinational circuit that convverts a single hexadecimal number to an equivalent BCD (binary coded decimal)number.
c) A 2 bit counter that counts till 2 that is the counting states are: 00,01,10,00,01,10,00.. .. .. etc