The number 24 is equal to (four factorial).
A number puzzle asks to construct 24 in as many ways possible using elementary mathematical operations on three copies of the same digit. Example solutions include
(1)
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(2)
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(3)
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(4)
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(5)
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(6)
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(7)
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(8)
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(9)
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where the not necessarily elementary "operation" of digit concatenation has been indicated using the symbol , any solution with 2 can be replaced with the trivial substitution , and all occurrences of and can be replaced by , , , , etc.