Put the digits 1 through 9 into the squares, using each digit once. Each circle contains the sum of the squares connected to it. Each red circle should contain the same number, and each blue circle should contain the same number. The answers to each puzzle are unique, but if you need to know the numbers in the red circles, consult the hints on a separate page.

1.

2.

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3.

4.

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5.

6.

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The hints are here.

The solutions are here.