Any logic circuit, no matter how complex, may be completely described using the Boolean operations, because the OR gate, AND gate, and NOT circuit are the basic building blocks of digital systems.
This is an example of the circuit using Boolean expression:
If an expression contains both AND and OR operations, the AND operations are performed first (X=AB+C : AB is performed first), unless there are parentheses in the expression, in which case the operation inside the parentheses is to be performed first (X=(A+B)+C : A+B is performed first).
Circuits containing Inverters
Whenever an INVERTER is present in a logic-circuit diagram, its output expression is simply equal to the input expression with a prime (') over it.
