6.RP.3 Use ratio and rate reasoning to solve real-world and mathematical problems
Differentiation:
For gifted students or younger students you could change the percentage amount to make it easier or more challenging to figure out the "winner's tax."
In this game students roll a dice and depending on the number they rool they put that many chips in a cup. At the end of each round the students must count up their chips and winners must put a 20% "winner's tax" back into the cup for the next game.