Thursday, August 5, 2010

Book Review: Great Estimations (teaching estimation)

I am in love.

With a book.

Two, actually.

(It really did get to be a bit ridiculous...  Yesterday in my math/lit class, when I introduced a new book I frequently began with, "I LOVE this book!" They finally laughed. Cause they knew it was true!)

Anyway, I love the Bruce Goldstone books on estimating--
Great Estimations and Greater Estimations. They are sorta like the "I Spy" books on steroids. The illustrations are bright, vibrant, colorful and include photos of everything from jellybeans to penguins to ducks. (On his website, Goldstone apologizes for the prolific use of ducks, saying, "Sorry about all the ducks. I bought 96 dozen* of these guys for Greater Estimations, so now I feel like I have to use them.) *My bold...can you imagine 96 dozen plastic ducks????

In Great Estimations, Goldstone teaches the reader to estimate, first by training the eye to see groups of objects (10, 100, 1000.) Later, you see sets of 10, then 100 objects, and are asked to estimate how many of the objects are pictured on an adjacent page. It's really quite clever.  He then demonstrates how to count the items in a small portion of a photo (like 1/100th), using that knowledge to determine the amount on the entire picture.

Greater Estimations begins in the same way, but extends learning by teaching new estimation strategies such as clump counting and box and count. Toward the end of the book, Goldstone suggests ways to estimate length, height, weight, size, and capacity.

My students--both children and adults--enjoy trying their skills on The Estimatron. (Check back for the link--looks like his website is currently under construction.) Located on Goldstone's website, this game allows you to estimate computer-generated groups of shapes up to 100, 500, and 1000.

If you introduce the books or game to your children, reinforce the idea that estimation is about making a good guess. It is not about getting an exact answer. When using the estimatron, even adults sometimes insist that they want to know if they got the "right answer."

In Marilyn Burns' book, Math, Facing An American Phobia (excellent read!), she stresses the importance of both mental math and estimation, two subjects that are rarely taught in "math class." Thankfully, books like Goldstone's can bring a new, fun, awareness to an often neglected topic.

For your entertainment, here's a bit of estimation trivia that one of my (adult) students shared yesterday. She said, "Estimate: how many Starbucks are found in the Seattle City limits?" [Her answer is at the bottom of the post.**]

[For additional lesson ideas, Google "estimation lesson plans." I estimate you'll come up with about 15,000,000 hits!]