# Probability : Addition and Multiplication Rules

It can be easy enough to get the addition rule and the multiplication rule confused. Tell me the difference between the two. Provide the notations and then tell me what type of problem I would use each one for.

Addition Rule:

Notation for Addition Rule: P(A or B) = P(event A occurs or event B occurs or they both occur).

Multiplication Rule:

Notation: P(A and B) = P(event A occurs in a first trial and event B occurs in a second trial).

#### Solution Summary

Probability addition and multiplication rules are discussed. The response received a rating of "5" from the student who originally posted the question.