List

The Value of Working Systematically

How old am I?
problem
Favourite

How old am I?

Age
14 to 16
Challenge level
filled star empty star empty star
In 15 years' time my age will be the square of my age 15 years ago. Can you work out my age, and when I had other special birthdays?
Odds and Evens made fair
problem
Favourite

Odds and Evens made fair

Age
14 to 16
Challenge level
filled star filled star empty star
In this follow-up to the problem Odds and Evens, we invite you to analyse a probability situation in order to find the general solution for a fair game.
Sorted
problem

Sorted

Age
14 to 18
Challenge level
filled star empty star empty star
How can you quickly sort a suit of cards in order from Ace to King?
A long time at the till
problem

A long time at the till

Age
14 to 18
Challenge level
filled star filled star filled star
Try to solve this very difficult problem and then study our two suggested solutions. How would you use your knowledge to try to solve variants on the original problem?