4   0
  2  

Make the sum of these number add up to six.

Going across, down, corner to corner. Using the number 4, 2, 0 only.

Hi Ginger,

To make the sum of the middle row be 6 the center entry must be 2. Then, to make the sum of the middle column be 6 the entry in the center of the first row must be 2. Thus you have

  2  
4 2 0
  2  

Now look at the first column. Either the top entry is 2 or the bottom entry is 2. Suppose that the top entry is 2, then the bottom entry must be 0. Hence you have

2 2  
4 2 0
0 2  

At this point you can't complete the puzzle. If the bottom right entry is 4 to make the bottom row sum to 6, then the diagonal sum is 8.

The only choice you made was putting a 2 in the upper left corner. Thus, suppose that the 2 is in the bottom left corner, then the top left corner is 0 and this time you can't fill the top right entry.

0 2  
4 2 0
2 2  

Hence the array you started can't be completed to satisfy the conditions given.

Penny