Logic Masters Deutschland e.V.

!

(Published on 20. March 2022, 14:40 by RockyRoer)

Teaser Question:

This puzzle is much easier if you try to do it without a calculator. This question will help you get going in the right direction.

How many zeroes are at the end of 400!

(recall 400! = 400*399*398*...*3*2*1)

The Rules:

  1. Normal sudoku rules apply.
  2. The numbers in each cage cannot repeat, and must multiply to some factorial number. The totals must be determined by the solver. Recall the factorial numbers are the following:
    • 1! = 1
    • 2! = 2
    • 3! = 6
    • 4! = 24
    • 5! = 120
    • 6! = 720
    • 7! = 5040
    • 8! = 40320
    • 9! = 362880
    Be careful, while 4! is defined as 4x3x2x1 -- it is also equivalent to 4x6 or 3x8, so a cage could be satisfied with either of those.

The Puzzle:

Link to f-puzzles Link to CTC-App

Solution code: The number of zeroes at the end of 400! followed by the digits in column 5 from top to bottom.


Solved by kolot, Arashdeep Singh, DVFrank, mathpesto, Playmaker6174, SudokuExplorer, bigger, Jesper, Christounet, twobear, SKORP17, Lara Croft, galgamer, universe42, Nylimb, Vebby, SXH, yangduoxing, zhangjinyang
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Comments

on 22. March 2022, 05:43 by twobear
Very nice puzzle! I kind of underestimated the puzzle after seeing all the comments prior to my solve... closer to 3.5 stars for me :p

Last changed on 22. March 2022, 01:16

on 22. March 2022, 01:09 by Christounet
Nice puzzle ! Took me nearly as much time to do the puzzle as to figure out the number of zeros at the end of 400!

Reply: ha ha! Sorry? Not really… Hope you learned something. I am a math teacher after all. Posted a blog post on this question a few years ago, if anyone is interested: http://rockyroer.blogspot.com/2013/04/how-big-number-is-400.html I had forgotten it until I googled it myself and discovered my own article. Lol.

on 21. March 2022, 16:23 by SudokuExplorer
Fun and fairly easy puzzle, thanks! :-)

on 21. March 2022, 15:58 by Playmaker6174
A very fun and neat solve once I wrapped my mind in completely, quite funny how the solve turned out :}

on 21. March 2022, 14:40 by mathpesto
Very impressive setting and such an enjoyable solve! I loved the minimalism of the grid and the many deductions I was able to make throughout!

on 20. March 2022, 18:52 by DVFrank
What a great puzzle! Thanks for setting this! :^)

on 20. March 2022, 15:43 by kolot
Perfectly designed puzzle. Not too hard for me, 2.5~3 stars ;-)

Difficulty:4
Rating:89 %
Solved:19 times
Observed:5 times
ID:0009F2

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