get_the_ID(); – now how to pass it?

Hello,

so i figured out how to display the page ID on the page.

echo get_the_ID();

how do i get it so that page id is passed along as a variable?

like i want the page id to = $passthepageid

so that way if a visitor is on a page that has an id of 2, then $passthepageid would = 2.

Thanks!