Bball tournament, 8 teams play eachother once

What's the number of games in tournament?

Aside from making a list counting out the possibilities,

How can you quickly figure this out, and what is the reasoning behind it?

I figured

(8 teams) *(7 "each team can play this # teams" )* (1 game/2 teams)

so 28 is answer, which is the same i get when making a list of all the possibilities by hand.

but am not sure what 7 exactly refers to--

Looks like the number of other teams each team could play against.

What would you describe it as? (what it is called doesnt seem to "cancel out" here--but what is it called anyways)

PLease let me know what you think !! thanx