A Youtube video from ProfRobBob in which he goes over the General Addition and Multiplication Rules in Statistics. He shows how a Venn diagram can help with the General Addition Rule. He also explains how we started to learn conditional probabilities when we did row and column percents in 2 way tables.
In this Youtube video mattemath reviews the basic multiplication rule for compound probabilities involving "and statements" that denote sequential events. He discusses the need for a modified form of the formula for dependent events, since the first event could affect the second event.