A circuit outputs a digit in the form of $$4$$ bits. $$0$$ is represented by $$0000$$, $$1$$ by $$0001..., $$ $$9$$ by $$1001.$$ A combinational circuit is to be designed which takes these $$4$$ bits as input and outputs $$1$$ if the digit $$ \ge 5,$$ and $$0$$ otherwise. If only $$AND,$$ $$OR$$ and $$NOT$$ gates may be used, what is the minimum number of gates required?

Which are the essential prime implicants of the following Boolean function? $$F\left( {a,b,c} \right) = {a^1}c + a{c^1} + {b^1}c$$

The Boolean function $$x'y' +xy +x'y$$ is equivalent to

Let $$A=1111$$ $$1010$$ and $$B=0000$$ $$1010$$ be two $$8$$-bit $$2's$$ complement numbers. Their product in $$2's$$ complement is