# The Value of Working Systematically

## The value of working systematically

Mathematicians often talk about the importance of working systematically on a problem, rather than approaching it in a random, unstructured way. The tasks in this feature have been chosen because systematic approaches will offer the most efficient routes to the solutions.

### How Old Am I?

##### Stage: 4 Challenge Level:

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

##### Stage: 4 Challenge Level:

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

##### Stage: 5 Challenge Level:

How can you quickly sort a suit of cards in order from Ace to King?

### A Long Time at the Till

##### Stage: 4 and 5 Challenge Level:

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?