Possessive Nouns

Possessive nouns are used to indicate ownership.
Possessive nouns usually are formed by adding an apostrophe (') and s.
John's book
Kerry's car
Grandma's mirror

When a noun is plural and ends in s, just add an apostrophe (').
The kids' toys
My parents' house
The teachers' lounge

If two people own one thing, add the apostrophe and s to the second person only.
John and Mary's new house
David and Sue's wedding
Tom and Doug's car

If two people own separate things, add the apostrophe and s for each person.
Susan's and Beth's books
Jean's and Dan's pants
Ben's and Jim's offices