# A billion pennies and counting….

Dec 16, 2005 by

How much is a billion, really? There are over 6 billion people living in the world. The Iraq war is costing us tens of billions of dollars. Recovery from hurricanes this year is costing us billions of more dollars. As this large amount becomes increasingly used in our world, do students (or myself for that matter) really understand just how much that is? Many elementary teachers (and some secondary teachers) use a fantastic book called “How Much is a Million?” to help develop number sense and place value for large numbers. The Mega Penny Project does the same thing with pennies, and computer 3D modeling.

While that didn’t seem overly special or exciting at first, it started to make sense once they (the authors of the site) started comparing larger numbers of pennies to real world objects. For example, one million pennies, stacked in a foot wide wall, is the height of an average man. One billion pennies makes 5 complete stacks of change, each stack roughly the size and shape of a full-size school bus. What’s really nice is that beyond the simple comparison for size, it also gives the height, weight, thickness, and area (if laid flat) of the pennies. A highly useful site for math classes as using real world objects for comparison really helps learners get a feel for just how massive millions, billions, and quadrillions are. That and extra reasons to talk about area, dimensions, and dollar values make this a useful site for several mathematics and real world concepts.

My favorite? The Sears Tower comparison. It would take a little more than 2.6 trillion pennies to equal the same amount of space that the Chicago skyscraper takes up.