The game you play where you eliminate as many sticks as you want and whoever ends up with the last stick loses

Question

The game you play where you eliminate as many sticks as you want and whoever ends up with the last stick loses

Answer 1

pick up sticks

Answer 2

Nim.

There are actually a couple different versions.  In one you start with 21 things (match sticks work) in the pile and take turns taking 1 through 4 of them.  Whoever is forced to take the last one loses.  The "trick" is to keep the number of items left in the pile to be a multiple of 5 plus 1: 1, 6, 11, or 16.  All you have to do to win is let your opponent go first, and then always take 5-what they took.  e.g. They take 1 --> you take 4.