Description: Pupils choose two numbers X and Y and find their mean. Then they replace X with Y and replace Y with the mean. They find the mean of these two numbers and then, using an iterative process, investigate what happens.
It is intended that this investigation be done using a calculator or computer
Suitability: Pupils working at all levels;individuals or pairs
Time: 1 hour upwards
Equipment: Calculator or computer spreadsheet for introduction and/or to work through examples as required
Key mathematical language: Mean, iterate, converge, limiting value, conjecture, decimal places, rounding, variables, algebraic expression