Number Code Puzzle

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Hello mathematicians, puzzlers, and other curious people!

For your entertainment, here\’s a puzzle that was posted in a math group on Facebook. (Wording adapted a little.)

How many unique three-digit codes can be formed, using the digits 3, 4, 5, 6, 7, 8, and 9 following the rules below?

  • code must be between 400 and 600
  • digits may be repeated
  • code must be divisible by 5

See what you can do with this and I\’ll post my ideas after folks have had some time to work on it.

Calc You Later!


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