I counted the coins in order, bronze, silver, gold. I scratched out the numbers on a brick in the wall above where the treasure chest was as I went, then did some quick calculations, and then divvied up.
I was short by a few gold.
I started from the gold this time, scratching the numbers into the wall, but the numbers were right, so I redid the division.
I was over by a few silver.
I would have recounted them yet again, but at this point the mimic tired of playing with me, and stopped pretending to be a wall.