This article explains how tree diagrams are constructed and helps you to understand how they can be used to calculate probabilities.

When two closely matched teams play each other, what is the most likely result?

Imagine flipping a coin a number of times. Can you work out the probability you will get a head on at least one of the flips?

Alison and Charlie are playing a game. Charlie wants to go first so Alison lets him. Was that such a good idea?

If everyone in your class picked a number from 1 to 225, do you think any two people would pick the same number?

What is the chance I will have a son who looks like me?

Can you work out which spinners were used to generate the frequency charts?

This interactivity invites you to make conjectures and explore probabilities of outcomes related to two independent events.

Which of these games would you play to give yourself the best possible chance of winning a prize?

Is this a fair game? How many ways are there of creating a fair game by adding odd and even numbers?

Explain why it is that when you throw two dice you are more likely to get a score of 9 than of 10. What about the case of 3 dice? Is a score of 9 more likely then a score of 10 with 3 dice?

Chris and Jo put two red and four blue ribbons in a box. They each pick a ribbon from the box without looking. Jo wins if the two ribbons are the same colour. Is the game fair?

Four cards are shuffled and placed into two piles of two. Starting with the first pile of cards - turn a card over... You win if all your cards end up in the trays before you run out of cards in. . . .

Simple models which help us to investigate how epidemics grow and die out.

Your partner chooses two beads and places them side by side behind a screen. What is the minimum number of guesses you would need to be sure of guessing the two beads and their positions?