No. Sudoku uses the digits 1 to 9 only as labels. There is no adding or counting, just checking which numbers are missing from a row, column or box.
No. Sudoku is a logic puzzle. The numbers 1 to 9 could be nine letters or nine colors and the puzzle would work the same way.
What you actually do
- Look at a row, column or 3×3 box and see which numbers are missing.
- Work out which empty cells could take each one.
- Place a number when only one cell, or only one number, is left.
No sums, no averages. Patience and careful checking matter far more than arithmetic.
Where to start
New players do well on Easy (44 given numbers). The Sudoku solving techniques guide builds from single numbers to harder patterns, and how to play Sudoku covers every rule.