1. Invitations were sent to 53 relatives for a family get-together. Only 47 relatives came. How many relatives did not come?   2. Arthur weighs 20 kg. His mother is 51 kg. How much more is his mother's weight (in kg)?   3. Mr. Anderson will be 42 next year. His son is 30 years younger than him. How many years old is his son at present?   4. A family party has 26 adults, 2 boys, and 5 girls. How many more adults are there at the party than children?   5. Jack is 10 years old. His aunt is 30. How many years older than him is his aunt?