Sodoku requires no arithmetic skills.
The object of the game is to fill all the blank squares with the correct numbers.
Each row of 9 numbers must include all digits 1 through 9 in any order.
Each column of 9 numbers must include all digits 1 through 9 in any order.
Each 3 by 3 subsection of the 9 by 9 square must include all digits 1 through 9.