Let $n, m ∈ Z$ (integer set) , $(n, m) = 1$. Suppose that $d$ is a positive divisor of $mn$. Show that there exist positive integers $d_1$ and $d_2$ such that $d =$ $d_1$$d_2$ where $d_2$ divides $n$ and $d_2$ divides $m$.
Could someone explain how to approach this proof? I would greatly appreciate it!
Since it is assumed that d is a positive divisor of $mn$ we get $d_1$ and $d_2$, but I don't understand how $d_2$ divides $n$ and $m$, this is where I get confused.