Monday, March 16, 2015

[oxrbbspu] Casting out nines and permutations

Casting out 9s as a way of checking arithmetic does not catch errors in which digits get permutated.  Casting out 11s, 101s, 999s, and 1001s would catch adjacent permutations.

How is casting out 11s different from casting out 99s?

No comments :