If a sum invested gains 10% each year how long before it has doubled its value?

Keep constructing triangles in the incircle of the previous triangle. What happens?

Which set of numbers that add to 10 have the largest product?

Make a set of numbers that use all the digits from 1 to 9, once and once only. Add them up. The result is divisible by 9. Add each of the digits in the new number. What is their sum? Now try some. . . .

Nowadays the calculator is very familiar to many of us. What did people do to save time working out more difficult problems before the calculator existed?

Investigate what happens if we create number patterns using some simple rules.

Where will the point stop after it has turned through 30 000 degrees? I took out my calculator and typed 30 000 ÷ 360. How did this help?

Use the clocks to investigate French decimal time in this problem. Can you see how this time system worked?