### From Zero to Hero

Feb. 16th, 2009 04:48 pmWhen I was in first grade, my teacher was trying to get us to understand subtraction. "Whenever you take a larger number from a smaller number," she said, "the answer is zero. For instance, five minus seven is zero."

I raised my hand. "No it's not. It's negative two."

"Who taught you that? Your parents? Well, nevermind that, you'll confuse people. The answer is zero."

For what was neither the first or the last time, my teacher made me go sit in a corner and read while everybody else caught up.

What I wish she had said:

"You're right, the answer is negative two, but for a long time people didn't know about negative numbers? In fact, they didn't even know about zero! Mathematics started as a way for people to understand the world around them. If you borrow two candies from me, and then four candies from me, it's important for me to know that you owe me six candies, not one or five or three! Well, for a long time people didn't see a need for negative numbers. It was only about fourteen hundred years ago that an Indian man named Brahmagupta invented negative numbers, the same man who invented zero. If you'd like to know more about him, I'll show you where to look..."