counting principles 1.4

arrangements

the number of arrangements of n distinct objects in a row is n!

permutations

the number of arrangements of r objects chosen from n many distinct objects is called this

combinations

when the order of arrangement of the r objects is not important then you are more choosing them then arranging them. The number of ways of choosing r objects from n many distinct objects

multiplication principle

the total number of outcomes for such an event is found by multiplying the number of choices for each action in the event.

-each action must be independent

-action must be in a specified sequence or order, like stages

addition principle

the total number of outcomes for such an event is found by adding the number of choices for each possible action in the event

-the actions cannot happen at the same time