Money always interests pupils, so ask them to list a number of items, from cheap things such as a bar of chocolate, to more expensive selections such as a PC or a car, along with their prices in pounds and pence. Convert the prices into euro and cents (a useful exercise in itself). Now round these prices in two ways: 1. Round the prices correctly to an appropriate degree of accuracy (this can stimulate discussion - is it appropriate to round the cost of a bar of chocolate to the nearest euro, or a car to the nearest cent?).

2. Round the prices up, again to an appropriate level of accuracy.

What is the effect of the rounding up? How do changes compare for cheap and expensive items? By what percentage does it increase prices compared to rounding correctly?

The history of the metre is a good stimulus for geometry and measurement. If the distance from the North Pole to the equator is 10 000 000m, what is the distance around the earth? What assumptions do you make in your estimate?

Surveying gives a clear application of trigonometry: How could Delambre and Mechain use surveying techniques to measure the North-South distance from Dunkirk to Barcelona? Why was it useful for Mechain to erect pyramids of known height on hilltops? How tall is the tallest building in your school? How might calculating this height help you to map the perimeter of the school?

Discussion of different units of measurement can stimulate number work. Why is it useful to have units that are divisible by 10? Non-metric systems include using 12 (inches in a foot), 360 (degrees in a circle) or 60 (minutes in an hour). What are the advantages and disadvantages of these systems? This leads to consideration of factors, decimals and fractions.