Classroom topics in focus: Rock Paper Scissors

Written by Kristen Tripet

The reSolve team is about to commence writing a series of new resources as part of our work on learning progressions. The topics for our learning progressions are:

• Fractions: Foundation to Year 7
• Proportional Reasoning: Year 7 to 10
• Statistical Variation: Foundation to Year 10

Over the course of the year, trial versions of lessons will be uploaded onto the website and, as always, we would value your constructive feedback. Over the last few months, a few new sequences were put up onto the website as part of our review into the Year 5 to 8 resources. Rock Paper Scissors is a new resource in Year 6 exploring concepts in Probability.

In this lesson students explore the probability of winning a game of Rock Paper Scissors, based on the assumption that the results are truly random. They play several games against other students as well as a simulated game using cards, dice or a computer. The students use results from this game to determine how random the results really are in games against other people and in simulated games. Students are likely to see that, while the simulated games produce random results, human games do not.

A large study showed that it is possible to predict people’s likely moves based on whether they win or lose in their previous game. If a person wins, they are likely to play the same move again. But if they lose a game, they are likely to change their move in the next game. Using this information, you can work out a winning strategy!

• If you lose the game, the person who beat you is likely to make the same move again. This means you should play the move that was not played. For example, if you play Paper and your opponent beats you with Scissors, you should play Rock because your opponent is most likely to play Scissors again.
• If you win the game, the person who lost is likely to change their move. This means you should play the move that they just played. For example, if you play Paper and your opponent lost by playing Rock, you should play Rock because your opponent is most likely to play Scissors in the next game.

The focus of these lessons is the notion of randomness. In statistics and probability, a random process requires that all possibilities have an equal chance of being selected. The results display no recognisable pattern or regularities. The simulated games in this lesson of Rock Paper Scissors are random. However, there are observable patterns and regularities in the human form of the game and so the results of these games are not random.

Check out the resource. While it is marked as a Year 6 resource it could be used at many other year levels!