perplexus.info :: Just Math : Factorial Difference Digits

Factorial Difference Digits (Posted on 2014-01-12)

Determine the last two non-zero digits of 36! - 24!

Extra Challenge: Solving this puzzle without a computer program.

See The Solution Submitted by K Sengupta

Rating: 5.0000 (2 votes)

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re: A thought

| Comment 2 of 6 |

(In reply to A thought by Charlie)

Can't this problem be re-written as:

(24!)(36!/24! - 1)

36!/24! will have at least two terminal zeroes. So if we subtract 1, the last two digits of our answer will be 99.

Posted by Jyqm on 2014-01-12 13:47:53

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