Isaiah spent his first 4 tokens at Zap Zoo Arcade on a game of air hockey. Then he played his favorite game, Solar Scout, over and over until he ran out of tokens. Solar Scout costs 2 tokens per game, and Isaiah started with a bucket of 40 game tokens. How many games of Solar Scout did Isaiah play?
Isaiah spent 4 tokens at Zap Zoo Arcade, so he has 40 - 4 = <<40-4=36>>36 game tokens remaining.
Solar Scout costs 2 tokens per game, so Isaiah played 36 / 2 = <<36/2=18>>18 games of Solar Scout. Answer: \boxed{18}.