Cross Sums are crossword puzzles using numbers
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CROSS SUMS
The Contest Center
Wappingers Falls, NY 12590
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 Here is a selection of Cross Sum puzzles, carefully ranked from easiest to hardest.        Your job is to fill the numbers from 1 to 9 into the 9 empty boxes so that the arithmetic in each row is correct. The math operations are performed from left to right. So to evaluate 1+2×5 you first add 1+2 to get 3, and then multiply that by 5 to get 15.        When performing the operations you may never go below zero, and each division must be even. Thus you could not have 5-7+4 because 5-7 goes below 0, and you could not have 7÷2+6 because 7÷2 is not an even division, it has a remainder.        If you have never worked a Cross Sum puzzle before, CLICK HERE for a fully worked-out example and explanation.

Cross Sum #1
Difficulty level 1
 + × 42 × + ÷ × ÷ 28 - × + - + 13 23 10 8

Cross Sum #2
Difficulty level 2
 + - 5 - + × × + 12 + × + + - 1 5 63 53

Cross Sum #3
Difficulty level 3
 × + 29 + + × × × 108 × - + - × 9 72 5 12

Cross Sum #4
Difficulty level 4
 × ÷ 3 + + + × - 20 - - - - - 2 7 4 6

Cross Sum #5
Difficulty level 5
 + - 9 + - - × × 12 + + + + + 21 10 11 8

Cross Sum #6
Difficulty level 6
 - + 10 + - - - × 12 + - × + - 3 15 0 4

Cross Sum #7
Difficulty level 7
 + - 5 × + - - ÷ 1 + × × + + 14 22 40 9

Cross Sum #8
Difficulty level 8
 + + 16 - × + + + 18 + + × - + 9 4 19 72

Cross Sum #9
Difficulty level 9
 - × 6 + + + + × 30 + ÷ + - × 6 19 1 12

Cross Sum #10
Difficulty level 22
 + + 17 - + - - ÷ 1 + + + + + 18 5 12 10