five is a cardinal number that represents the quantity of five individual items. It can be used in a general sense to count objects or e.g. refer to a decade (the fifties).
1. There are five pieces of pie on the counter.
2. She is one of five members of the student council.
3. On their fifth anniversary, they went on a vacation with five close friends.
the common mistake with five is mixing up the pronunciation of the number (e.g. fife vs. five).