[Math Lair] Phone Equations

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Phone equations can be an interesting recreation, especially for younger mathematicians. The idea is pretty simple. Take a seven-digit phone number (ignoring the area code, just use the exchange and local parts of the number). Change the hyphen to an equals sign, and by inserting any mathematical symbols between or around the numbers, create a true equation. For example, if you were to use the phone number 522-4833, you might come up with:

5 × 2 + 2 = 4 + 8 - 3 + 3
52 + 2 = 48 + 3 + 3

Here are a few to try. Answers can be found on the answers page.

  1. 576-5458
  2. 327-6951
  3. Your own phone number

If you're interested in thinking deeper, you may want to ask yourself whether every phone number can be written as an equation using only the basic arithmetic symbols (and brackets) or some other set of symbols.

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