Yes, depending on the ability you might let them use two numbers. We have a running joke in class that if I hear 7 = 20-13 I am likely to burst into tears. For my more able, I specify that they must use at least 3 numbers each time or for the really able, they must use all four. So 1 = (6 – 5)^(20+13)

Here is a link to a simple resource for this I put on the TES website:

http://www.tes.co.uk/teaching-resource/The-Date-Game-6313167/

Sometimes I ask students for answers and write them up, sometimes I get them to write up the answers on the IWB. There’s always something that comes up of interest, e.g. 7 = 13 – 20 and there is always a discussion to be had an square numbers, square roots and factorials. My Year 7 (grade six) class are now so familiar with factorial notation it’s brilliant!

The date game, they create an expression using those numbers to try and create the numbers 1-9?

Ex. 5,6,20,13

6-5=1, so one is taken care of

To make it more challenging, I stipulate that they must use 3 or more numbers each time.

It’s a great starter, different every day and the students genuinely enjoy it. I have students who I taught many years ago who still talk about it!

I love (and the students really love) to play Nim on the IWB. I like a slightly different alternative called Pick It. Place dots around a polygon, students take it in turns to pick one or two dost, the winner taking the last dot. However, two dots can only be taken if they lie on the same edge. It’s an interesting game for students to analyse and come up with optimal strategies.

I programmed SAGE to tell me the winning and losing positions up to n=200, but it’s really not at all obvious what the pattern is just from looking at the data. I got it eventually, but only because of instincts that I never would have had if it weren’t for Nim and its ilk.

In your example, isn’t “1, 2” the losing move? ~_^