you are viewing a single comment's thread
view the rest of the comments
[–] 2 points 4 months ago*

oh that's easy. all multiples of three, you add their digits and the digits add up to three.

also if you've made a transposition error (179 instead of 197) you will be off by a multiple of 9.
sorry bookkeepers i just gave away your trade secret. the one.

  • source
  • parent