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Marty R. · Posted: Wed Mar 22, 2006 6:00 pm Post subject: Checking completed puzzles

When I finish a puzzle, I scan each row, then each box to make sure there are no duplicates. Is it also necessary to scan each column? Or is checking just one of the groups (row-column-box) adequate?

keith · Posted: Thu Mar 23, 2006 1:02 am Post subject: Why bother?

Marty,

If you make a mistake, you will notice it long before you complete the puzzle. I do not bother to check completed puzzles.

If you feel you must check, then you must check blocks, rows AND columns. Here is why:

Start with a completed correct puzzle. Interchange two numbers that are in the same row and block. The row and block will still have 1 - 9, the only way to find this "mistake" is to look at the columns.

Keith

Marty R. · Posted: Thu Mar 23, 2006 5:50 pm Post subject:

Thanks for the explanation Keith.