Deal or no deal? by Katie Slusar

Who is it for?
What is outlined below is a maths lesson which could be adapted to suit a range of ages and abilities looking at the topic of averages. Whilst the lesson below is clearly a maths lesson I would be interested to see if it could be adapted to suit other subjects.

Outline of idea
The lesson was playing the game deal or no deal, more commonly seen on channel 4, to see what maths lies behind it.
How the game works on channel 4:
There are 22 sealed boxes, one per contestant, each containing a different amount of money varying from 1p up to £250,000. A contestant is selected at random to play the game. They have to select five people per round to open their boxes and show the amount of money inside. They are then made an offer at the end of each round by the banker. If they would like to then they can sell their box to the banker for that amount of money – what happens more commonly is that they keep on playing, risking that their box will have more in it than the banker is willing to offer. Hence deal or no deal.

The difference when playing this game in lessons was that instead of large red boxes the students were each given a matchbox (painted red with a big number on it) which had an amount inside. The beauty of this is that you can easily swap the insides around to play the game multiple times. We appointed one banker and one contestant. The game continued through each round but at the end of the round the banker had to come up with an offer – as a class we discussed the mean and median of the amounts left and considered how these changed through the game, the banker was given the final say on what offer they wanted to give. As a class we then talked about what the contestant should do at each stage – what was the probability that their box would have more in it than the banker had offered? What was the probability that it would have less?
How it worked out
The activity was received very positively by the students, the particularly enjoyed building up the tension and acting like game show contestants e.g. ‘You’ve been great man, I hope it’s a good one for you’.

Regularly the banker gave very low offers; it might have been interesting to play the game repeatedly and see if the banker came away worse overall or well off – encouraging students to see that a deal could be a positive thing for the banker as well.

Next steps

It would have been interesting to finish the lesson by looking at a video of deal or no deal and seeing how close the banker’s offers were to the average on each round.
I would also be interested to see if you could graph the bankers offers and see how they change over time, when looking at the real thing on TV I wold expect the bankers offers to increase over time as the game draws to a conclusion and the banker begins to think that a deal may be the most desirable outcome.