last free cell
level 1 - super easythis is the easiest sudoku technique. perfect for beginners and kids!
what it means
when 8 numbers are filled in a row, column, or box, the empty spot gets the last number. it is that simple!
the rule:
each row, column, and 3×3 box must have the numbers 1-9 exactly once. if 8 are there, you know what the last one must be!
example: a row
look at this row. 8 numbers are filled. what is missing?
numbers present: 1, 3, 4, 5, 6, 7, 8, 9
missing number: 2
example: a column
the same idea works for columns. look at the middle column going down.
numbers present: 1, 2, 3, 4, 5, 6, 7, 8
missing number: 9
example: a 3×3 box
it also works for the 3×3 boxes. look at the top-left box.
numbers present: 1, 2, 3, 4, 5, 6, 7, 8
missing number: 9
how to do it
- 1
look for a row, column, or box that has 8 cells filled in.
- 2
count the numbers from 1 to 9. which one is missing?
- 3
fill in the empty cell with the missing number. you solved it!
pro tip
always look for rows, columns, or boxes with the most numbers filled in first. these are the easiest spots to solve and will help you fill in the rest of the puzzle!