Sets

If P = {$$x$$ : $$x\,\,\epsilon\,\, W$$ and $$4 \leq x \leq 8$$} and Q = {$$x$$ : $$x \,\,\epsilon\,\, N$$ and $$x < 6$$}.
If $$A=\left\{ 2, 4, 6, 8, 10\right\}, B=\left\{1, 3, 5, 7\right\}$$ find $$(A\cup B)$$
if a= all even natural numbers 
b=all odd natural number s
Can you say a and b are which type of sets 
If $$\displaystyle A=\left \{ 2, 3, 5 \right \}, B=\left \{ 2, 5, 6 \right \}$$ then  $$\left ( A-B \right )\times \left ( A\cap B \right )$$ is
How many fitters are welders but not both