Basic probability
Nobody can say how a single toss will land. What can be said, and how does it become a number?
Where you are 13 inside
What this area is about
A probability is a number from 0 to 1 that says how likely an event is. There are two ways to get one: reason it out from a model of the situation, or run the process many times and count. This area builds both.
How these fit together
Words and notation. What randomness means, the scale of chance, outcomes and events, the complement (P(\text{not } A) = 1 - P(A)) and odds.
Probability from a model. Listing a sample space and counting outcomes, which works only when every outcome is equally likely; probability models for when they are not; and area, when a point lands anywhere in a region with no part favored.
Probability from trials. Experimental probability counts results. The law of large numbers says that over many independent trials with the same chance, the running share settles near that chance. Designing a simulation and estimating from its trials put that to work.
A path through it
Randomness first, then the chance scale and outcomes and events together (each refers to the other). Next the sample space and counting outcomes, then the complement, which probability models need. Area and odds follow, then experimental probability.
The law of large numbers also assumes compound events, which build on the lessons above, so take that area next. Then the law of large numbers, designing a simulation and, last, estimating from it.