From the given sets, list the common elements and the common elements of each pair of sets in diagrams.

ai) Members of set $A=\{3,6,9\}$ are $3$, $6$, $9$.
Type: multiples of $3$.

b) Set $P=\{2,3,5,7\}$ contains the prime numbers $2,3,5,7$.

ii)
Step 1: List elements of $P$: $2,3,5,7$.
Step 2: Count distinct elements.
$n(P)=4$.
4

1a)
Step 1: List whole numbers $\leq 5$: $0,1,2,3,4,