1. Invitations were sent to 85 relatives for a family get-together. Only 78 relatives came. How many relatives did not come?   2. Adam weighs 18 kg. His mother is 52 kg. How much more is his mother's weight (in kg)?   3. Mr. Douglas will be 43 next year. His son is 30 years younger than him. How many years old is his son at present?   4. A family party has 53 adults, 11 boys, and 13 girls. How many more adults are there at the party than children?   5. Peter is 13 years old. His aunt is 35. How many years older than him is his aunt?