At stake: two free tickets to the All-Star Game. And all you have to do is guess the correct number of jelly beans in a jar at the Planet Toys store. One particularly smart boy has an idea: Why guess when you can estimate? He plays a game with his buddy as they head over to the store on the bus. With four people per row, 10 rows, and a few folks standing in the aisle, he estimates that there are 43 people on the bus. "I didn't even need a pencil," he boasts.
Knowing how to estimate is an essential skill that helps children determine approximate totals as well as check the reasonableness of their solutions to problems.
Illustrated by S.D. Schindler.
Read the story together and ask your child (or students) to describe what is going on in each picture. Ask questions throughout the story such as "What would you do to estimate how many people are on a bus?" and "How would you estimate the number of cars in a traffic jam?"
Together, make up your own Betcha! game. Pick something that is difficult to count, such as people in a long line, cars in a parking lot or cookies in a box. Help your child (or students) consider different strategies for making these estimates. Then check to see how close these estimates are to the real numbers.
Teacher Idea: You can use the MathStart books to introduce a concept as well as to reinforce a concept. An example would be "Betcha!" I usually read the book at the beginning of the year because we do estimation activities all year long. The kids can see how the kids in the story use different strategies for estimating. My students have to bring in their own estimation jars at least once a year. Everybody gets a chance. So it can be container of whatever—rocks, candies, straws. I’ve even had grass. They bring in all kinds of stuff. One kid brought in shark teeth from Florida, which was really neat. Sometimes I’ll give the winning estimator a pencil or a piece of candy, but mostly it’s about the glory.—Richard Callan, Bunker Hill Elementary School, Indianapolis, IN