Bodies are created in proportion. When a person or animal grows in height, the rest of the body grows as well. Help your sixth graders see the connection between the mathematical and biological concepts with this fun math activity. Kids bring a doll or stuffed animal to class, and then use a measuring tape to find out how much taller they are than the dolls. Using this value, kids calculate how big the other body parts would be if the doll were to become life-sized.