How can the numbers 1 2 3 4 equal 47?

Answer 1

Using all numbers once:

4^2 x 3 - 1 = 47

[42 x 3 -1 = 47]

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Simpler is 41+(2x3) = 47

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To use them in that order, you could use the sqrt function

1 + (23)(sqrt 4) = 47