Birthday Gift: Revision history

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14 February 2023

  • curprev 06:2906:29, 14 February 2023 Kmk21 talk contribs 3,822 bytes −1 No edit summary
  • curprev 06:2806:28, 14 February 2023 Kmk21 talk contribs 3,823 bytes +351 No edit summary
  • curprev 03:4303:43, 14 February 2023 Kmk21 talk contribs 3,472 bytes +3,472 Created page with "Boiling it down, this problem asks us to count the number of 'a' digit numbers which are equal to 'b' mod 225. We first notice that 'a' is 10^18, so far too large to do any math on or even iterate through. We also notice that 225 is an oddly specific number, and factoring, we find that it is 25 * 9, both factors of which have straightforward divisibility checks, whereby x % 25 = 0 is demonstrated by the last two digits being 00, 25, 50, or 75, and x % 9 = 0 demonstrated..."