Fishing!
(Canada )
First you neeed a cardboard box. With the child or children paint the outside so it looks like an aquarium, on the inside put several paper fish.
Each paper fish should have a number and paper clip on it.
Using a "fishing pole" (stick with string and a magnet on the end) go fishing. When they catch a fish, put the number on a piece of paper and ask them to help you add them up each time they "catch" a fish.
The first person to get 50 points wins!!!