Adults
know that estimation is an important lifelong skill. We use it so often we are likely not even
cognizant of the myriad ways estimation saves us time and effort. The most memorable time estimation played a
role in my life was when I won the jelly bean estimating contest at Eddie’s of
Roland Park when I was 8 years old (yes, your children are learning from an estimating professional)
– but it was certainly not the last time I put my estimating abilities to
work!
Estimating
is a skill that takes practice and a trained eye. In class we looked at Bruce Goldstone’s
fantastic photographic book Great Estimations. In it, Mr. Goldstone models the skill of “clump
counting.” The idea is that if you can
recognize a clump of ten, then you can estimate a much larger amount by assessing
how many clumps of tens there are in total.
My guess: 3645. True total: 3653. Students: How close was my guess to the actual amount? |
Using
our digital camera and classroom supplies, students worked in pairs to photograph
their own pages of our class estimation book.
First, students counted out ten of their object and took a picture. Then, after adding a handful or two (or
three, or four!) more, students photographed a much larger collection of their
item. After estimating how many groups
of tens there were altogether, students were allowed to count the exact amount. The final product is our very own guess-and-check
estimation book.