## Sunday, March 27, 2011

### Roots and Fingertips

(A hodge-podge today.) Two quick notes that I want to jot down for myself.

The first is for our Botany unit. One of the topics we are covering this week is Roots: type and function. I want to introduce it with a wonderful book of poetry that I first found on the shelf at the local library as part of Black History Month. I saved it for this unit.

Roots and Blues: A Celebrationby Arnold Adoff

Roots sustain you. They dig deep into the soil to hold the plant, give strength, give a sense of place.

The other surprising observation I made last week was about the word "digit." We had a visitor some into the classroom and before he talked about binary and hexadecimal number systems (he works on weather satellites), he asked the children about the number system we all usually use every day. It has ten digits, right? And he held up his finger and wiggled them. And I thought, AHA. Digits! Like fingers... I don't know why I had never figured that out before.

I had a world of trouble helping my students understand the math term "digits" until it finally came to me, to tell them that digits make up a number like letters make up a word. Digits are actually more complicated than that, because the place they occupy in the number is what gives the digit its value, but it was an easy way for them to shift to seeing the number as a whole to looking at the digits that make it up. For the first time (after that explanation) I would ask a child, how many digits are in this number, and they could tell me.

Do you know the mathematician who finally persuaded Europeans to ditch the obsolete Roman Numeral system?

His biography (and 14 others) can be found in Mathematicians Are People, Too: Stories from the Lives of Great Mathematicians, Vol. 2