Intro Probability

How the lesson starts: Intro Probability

Welcome to the fair!
Welcome to the Sunny Fair! Milo runs the game booths, with dice and prize bags. Before you play, you can predict your chances with a fraction. That's called probability. Why bother? So you know which games are worth a try. Step right up!
From 0 to 1
Probability is winning outcomes ÷ all outcomes, so it runs from 0 to 1. A bag has 10 red counters and 0 blue. Drawing blue? 0 out of 10: impossible! Rolling a 4 on a fair die: 1 face out of 6, so 1/6. Rolling even: 1/2. Drawing red? 10 out of 10: certain!
Let's roll for even
New game: win on an even number. First list all the faces: 1, 2, 3, 4, 5, 6. That's 6. Now the winners: 2, 4 and 6. That's 3. So the probability is 3 out of 6, or 3/6. Simplify: 3/6 = 1/2. Half the faces win!