What is the correct salutation and subscription for a letter to a stranger whose name you do not know?

Write a letter to the manager of a bookshop complaining that the books you ordered arrived damaged and asking for a replacement.

Write a letter to the librarian of your school requesting that the library be kept open for an extra hour after school.

Write a letter to your Principal requesting permission to remain absent from school for three days to attend a family wedding.

Write a letter to your cousin inviting him or her to spend the summer holidays with you and describing what you plan to do together.

List the six parts of a formal letter in order.

Write a letter to your grandmother thanking her for a birthday present and telling her how you spent the day.