Level 00 · Warm-up math
Chances, counted
What a probability is, why all the chances add up to 1, and what you see when you try something many times.
Lesson 1 of 5 about 9 min
How sure are you?
Before a cricket match, the umpire tosses a coin. Nobody in the stadium knows how it will land. But everyone agrees on one thing: heads and tails have the same chance.
A probability is a number that says how likely something is. It always sits between 0 and 1:
0 = never · 0.5 = 50-50 · 1 = certain
That one idea is the heart of this lesson. Let's use it. Where does each of these belong?
0 · never0.51 · certain
1The sun rises tomorrow
2A tossed coin lands on heads
3You roll a 6 with one die
4You roll a 7 with one normal die
GoalPut all four events in the right place.