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Star Product Sudoku

Age 11 to 16 Challenge Level:

Caitlin kept a record of the order in which she filled the Sudoku.

She filled the cell marked 1 first, then the cell marked 2, then the cell marked 3...

You might like to retrace her route to fill in the cells in the same order, though this is just one possible route through the problem.

You can print her journey here.