Unplanned uncertainties

Last week I was doing some voluntary mathematics teaching at my local primary school.  It is  small rural school with a KS2 Y3-Y6 class and I had planned to support the Y6 children.  However, moments before I was due to start I received a verbal message that the headteacher had to deal with a playground incident so could I do something with the whole class; oh the joy of being given a free reign. So I began by introducing the idea of:

“If we know (something) what else do we know?” type questions.

The first response was 2+2 = 4 so I restated the idea – “If we know 2+2 = 4, what else do we know” – and the responses starting happening  e.g.”4 – 2 = 2″, “4 = 2 + 2”. I suggested “20+20 = 40” and we were off again: “200 + 200 = 400”, “2000 + 2000 = 4000” then “2 million + 2 million = 4 million”. Some children talked about zillions and ‘squillions’… a fine generality, so I just had to ask the question: “What does 4 million look like?” and there we were – back at place value… and off again.  Crisis over, – headteacher returns… who knows what would have happened next.