If $\xi =$ the set of all digits in our decimal system, $A=\left\{x:x \mathrm{is} \mathrm{prime}\right\}$ and $B=\left\{x:x \mathrm{is} \mathrm{a} \mathrm{perfect} \mathrm{square}\right\}$, then the result $A\cap A\text{'}=\Phi$  is 

Let $\xi =\left\{x:x\in N \mathrm{and} x\le 8\right\}, A=\left\{x:5<x^2<50\right\} \mathrm{and} B=\left\{x:x \mathrm{is} \mathrm{a} \mathrm{prime}\right\}$. Draw a Venn diagram to show the relationship between the given sets. Hence, list the elements of the set $A-B.$

Is $A-B=A\cap B\text{'}?$