1. Invitations were sent to 13 relatives for a family get-together. Only 4 relatives came. How many relatives did not come?   2. Arthur weighs 20 kg. His mother is 55 kg. How much more is his mother's weight (in kg)?   3. Mr. Martin will be 40 next year. His son is 27 years younger than him. How many years old is his son at present?   4. A family party has 48 adults, 17 boys, and 3 girls. How many more adults are there at the party than children?   5. Gary is 16 years old. His aunt is 36. How many years older than him is his aunt?