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A Millionaire By Doubling Pennies

Start with a penny. Double it daily. When will you be a millionaire?

Photo by Maura Teague

Here’s a quick opener for your school day. Write this on your board as kids walk in:

On day one, you have one penny. On day two, you double it. Then, you double your total again on day three. If you keep this up, how many days until you’re a millionaire?

Before they tackle it, first ask them to guess. A year? Six months? If they’re reluctant, do as Dan Meyer says, and ask for “too low” and “too high” guesses. It’s probably not a week. It’s probably not a century.

Then let them go at it. Depending on your students’ ages, they’ll probably try tackling this in all sorts of ways. Once they hit the (surprising) number, ask for all of the different methods they used.

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This is an example of “Get Ridiculous”

Avoid boring examples and go for the outliers! Everything's more interesting when you're working with unexpected examples.

See other examples of “Get Ridiculous” ❯❯

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