How to label the 13th floor

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  1. Further evidence that explaining the joke ruins it.

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  2. Except that the absolute value is unnecessary, the square root of 169 is 13, it can’t be -13, otherwise square root wouldn’t be a function.
    So the joke is more of a fail.

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  3. 12′

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    The second and third paragraphs explain this. The square root sign denotes the positive square root. If you are referring to the negative root, you just put a minus sign in front of it. If you are referring to both roots, you use the ± sign. 🙂

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