Question

$A\subset B$ then show that $A\cap B$ = $A$ (use Venn diagram).

Answer 1

Since $A$ is the subset of $B$, therefore, we have to draw a small circle $A$ inside the large circle $B$. $A\cap B$ means we have to shade common part of $A$ and $B$. The venn diagram is drawn below:

Hence, from the above venn diagram, we clearly observe that $A\cap B=A$.