---
title: "inclusion exclusion counting"
source: https://www.jemoka.com/posts/kbhsum_rule_of_counting/
---

If an outcome can be from sets \(A=m\) or \(B=n\) with no overlaps, where \(A \cap B = \emptyset\), then, the total number of outcomes are \(|A| + |B| = m+n\)
If there are overlap:
\begin{equation} N = |A|+|B| - |A \cap B| \end{equation}
