To become a good sudoku number player you must be able to "hold" a number(s) in your mind.
Medium1 Three-Grid Excercise
1
7
5
8
3
9
4
6
8
2
6
9
1
5
7
3
9
3
4
5
6
8
2
1
Above are three 1 to 9 number grids. Each grid is missing one number - determine the missing numbers - making a mental note of them. Now proceed to the three below grids. Determine the missing numbers in each - making a mental note of them, also.
8
1
3
6
9
7
5
2
7
6
5
1
8
2
9
4
2
9
3
7
4
6
1
8
Now recite all the above grid numbers. Repeat process until you can. (mentally repeating the numbers)
Ok, once able to do the above - proceed and determine the missing numbers in the three below grids.
2
3
8
5
9
4
6
1
6
1
7
2
8
4
5
9
5
9
1
6
7
3
8
2
Ok, now recite all the above determined missing grid numbers.