"Eli's Ladder" is the rarest educational video game in existence.
Eli's Ladder Box
Loose: 1500$
CIB: None
New: None
Players answer simple math questions to move Eli up the ladder and into his spaceship, all so he can fly to the moon. The game even includes a wall chart and motivational stickers, according to RacketBoy.
"Eli's Ladder" Game cartridge.