1. Generator of group

Let p and q be prime numbers. How many generators of the cyclic Group $Z_{pq}$

2. Originally Posted by GTK X Hunter
Let p and q be prime numbers. How many generators of the cyclic Group $Z_{pq}$
Let $a,b \in G$ such that $o(a)=p, o(b)=q$. What is $o(ab)$?

3. Originally Posted by Swlabr
Let $a,b \in G$ such that $o(a)=p, o(b)=q$. What is $o(ab)$?
$lcm(p,q)$ right?