how to solve: A'B'CD + A'BC'D' + A'BC'D + A'BCD' , A'BCD +
AB'C'D' + AB'C'D...
how to solve: A'B'CD + A'BC'D' + A'BC'D + A'BCD' , A'BCD +
AB'C'D' + AB'C'D + AB'CD' and A'B'C'D + A'B'CD' + AB'CD +ABC'D' .
solving by simple expression not by using k map.