This is the Challenger Puzzle, by Linus Maurer, found in the Saturday Toronto Star.

The rule is to fill in each empty square with a number, 1 thru 9.
The rows, columns and diagonals of the white square must add to the yellow numbers.

This applet can be used in one of two ways:
1. Enter the numbers as given in a puzzle and hit "Solve". The computer will solve the puzzle for you.
2. Hit "Random" and YOU solve it. Hit "Check" to see if you're right.

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