Numbering Squares:

The numbers 1 to 25 are to be placed on a black and white ( like a checker board) 5 X 5 grid so that each number, except 1, is next to, horizontally or vertically, the number one less than it. (note: all the corners are black squares)

 

a. Explain why the number 1 must be placed on a black square.

b. Explain why the numbers 1, 3, 5,7, 9 can not all be placed on one long diagonal.

c. Show that in a completed numbering the sum of the numbers on a long diagonal must be at least 33 and that 33 can occur.

Have you tried at all? What'd you get so far?

I have thought alot about it but i still have had no success..

please help me .

why don't you show us what you've done so far, so we have an idea of where you are up to.^.^ so we know you've given it a go.