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# Puzzles

## Archive

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## Backwards fours

If A, B, C, D and E are all unique digits, what values would work with the following equation?
$$ABCCDE\times 4 = EDCCBA$$

## 10 December

How many zeros does 1000! (ie 1000 × 999 × 998 × ... × 1) end with?

## 17 December

In March, I posted the puzzle One Hundred Factorial, which asked how many zeros 100! ends with.
What is the smallest number, n, such that n! ends with 50 zeros?

## One hundred factorial

How many zeros does $$100!$$ end with?
© Matthew Scroggs 2018