1. Invitations were sent to 55 relatives for a family get-together. Only 50 relatives came. How many relatives did not come?   2. Ronald weighs 19 kg. His mother is 56 kg. How much more is his mother's weight (in kg)?   3. Mr. Douglas will be 46 next year. His son is 33 years younger than him. How many years old is his son at present?   4. A family party has 51 adults, 16 boys, and 19 girls. How many more adults are there at the party than children?   5. Steve is 16 years old. His aunt is 45. How many years older than him is his aunt?