Tag Archives: innies and outies

This tip is probably the most important solving technique of Killer Sudoku, one that will save you a lot of time. It does involve some math, but very simple one. Basically, the whole story is that you have to bear in mind that 1+2+3+4+5+6+7+8+9 = 45. Very smart, huh? Well, maybe not so, but it’s […]