I just started statistics and need to use the general addition rule. I know what it looks like for $3$ events:
$P(A \cup B \cup C) = P(A) + P(B) + P(C) - P(A \cap B) - P(A \cap C) - P(B \cap C) - (2 * P(A \cap B \cap C)) + P(A'\cup B' \cup C').$
But I'm confused to exactly how it extends to 4 events?
Thanks.