# Complement and addition rules

A twelve-step interactive probability lesson with written Coach–Zon guidance, formula definitions, prediction prompts and examples connected to quantitative finance and machine learning.

Illustrative scenarios and fixed-seed simulations; independence and conditioning assumptions are explained on each step.

Canonical page: https://21ifm.com/probability/complements-addition

## Explore

- [Probability learning path](https://21ifm.com/probability)