# Understanding Large Numbers

It's a zillion!" calls out one student in response to my question of how to read the number 1,000,000,000 I've written on the overhead. "No, it's not, it's a million," argues another.

Despite the fact that my fifth graders have been taught place value throughout their elementary years, there is something about big numbers that lends itself to guessing. Perhaps it's the omnipresent state lottery advertisements that tend to blur big numbers together. Or more likely it's the fact that big numbers are just difficult to read, much less understand. Imagining a billion boggles my mind, whether I'm trying to fathom that number of galaxies swirling around the universe or the number of H 2 O molecules in a drop of water.

Kids are fascinated with big numbers, especially if they connect with the real world. Thanks to the U.S. government's addiction to military spending, students have an endless stream of large numbers to study. And those numbers just get bigger and bigger! The growth in the military budget comes as schools face massive budget cuts. Teaching about these matters provides students an opportunity to improve their understanding of large numbers, and even more importantly, understand the power of math in debates about the future of our communities and world.

Before I delve into budget issues, I do a couple of activities to help children put meaning behind place value. This year, the night before I was to start my mini-unit on big numbers and budgets, the students' homework was to ask family members what they thought one million and one billion meant. The next day students shared responses. They ranged from the precise "one million is one thousand thousands" to the comical "it's what you get when you win the lottery," to the practical, "it's enough money to buy everything we ever need and still have some left over."

I asked the students, "How many days equals a million seconds? After some initial guesses, the students worked in groups with calculators using different strategies to solve the problem. Eventually they came up with about 11.8 days.