You can't make XOR out of NOT alone. Mathematically, NOT takes only a single argument, and its gate, an inverter, takes a single input. There's no way to combine two inputs giving a single output...
AND gate is A.B If two not gates are added at both inputs of and gate then output becomes A'.B' which is equal to (A+B)' by DeMorgan's law. hence the nor gate is formed Update: Put more simply,...