You may also like

problem icon


Place four pebbles on the sand in the form of a square. Keep adding as few pebbles as necessary to double the area. How many extra pebbles are added each time?

problem icon

Happy Numbers

Take any whole number between 1 and 999, add the squares of the digits to get a new number. Make some conjectures about what happens in general.

problem icon

Intersecting Circles

Three circles have a maximum of six intersections with each other. What is the maximum number of intersections that a hundred circles could have?

Pocket Money

Age 11 to 14 Challenge Level:

Imagine your family agreed to give you some pocket money every day for a month! You can choose from the following options:
  1. £10 every day
  2. £3 on the first day, £3.50 on the second, £4 on the third, and so on, increasing by 50p per day
  3. 1p on the first day, 2p on the second, 4p on the third, and so on, doubling each day.
Without doing any working out, which one would you choose, and why?

In a month with 31 days, how much money would you have by the end of the month, under each system? You may wish to explore using a spreadsheet...

Here are some questions you might like to consider:
In which months would option 1 be better than option 2?
If your family stopped your pocket money on day 8, which option would give you the most?
On which day of the month does option 3 become the most fruitful?
If you chose option 3, how many days would it be before you became a millionaire?