I need help for Designing Digital circuit
using AND , OR, NOT gate


1. A binary addition subtraction that adds or subtracts two 4 bit binary numbers. The circuit has a selection bit that controls whether addition or subtraction is to be performed

2. Draw a combinational circuit that converts a single digit hexaecimal number to an equivalent BCD number

3. A 2 bit counter that counts till 2 that is the counting states are: 00,01,10,00,01,10,00....etc.


regards

Amol sathe