The case notes
How an X pair works
Digits on either side of an X add to 10. Watch a worked example, then try the idea in a puzzle.
Put it into practice
X means a pair totals 10
An X sits between two Sudoku cells. It tells you that the digits touching it add to ten.
4 + ? = 10
Here, one side of the X is four. The other side must make the pair reach ten.
4 + 6 = 10
Ten minus four is six, so place six beside the X. Four and six make ten.
Read the pair
Check the two cells on either side of each X. The mark gives their sum, not either digit on its own.
Read the transcript
An X sits between two Sudoku cells. It tells you that the digits touching it add to ten. Here, one side of the X is four. The other side must make the pair reach ten. Ten minus four is six, so place six beside the X. Four and six make ten. Check the two cells on either side of each X. The mark gives their sum, not either digit on its own.
