The best way to understand probability is to look at some examples.
title: Single Events

 

Coin toss

When you toss a coin, it could land on heads or tails. These are the only two possible outcomes.

The probability of falling on heads is 1 chance in 2 possibilities.

Mathematicians write this as P(heads) = 1/2 or 0.5

 

 

Dice roll

A dice has six sides. They are numbered 1, 2, 3, 4, 5, 6.

What is the probability of throwing a six?

3 in 6
2 in 4
1 in 6
6 in 1

What is the probability of throwing an EVEN number?

3 in 6
1 in 6
4 in 6
2 in 6


 

 

Click here for a calculator

These examples look at only ONE event. What happens if you have TWO coins or dice? Go to the next page for an experiment with two dice.