The numbers 1 to 64 are written in order on the chessboard above. What is the sum of the numbers in the yellow squares minus the sum of the numbers in the white squares?
0 is the answer,
In the below rectangle, all the smaller shapes are squares. If the two yellow squares in the center have length 1, what is the area of the rectangle?
64 numbers (not necessarily distinct) are placed on the squares of a chessboard such that the sum of the numbers in every 2x2 square is 7.
What is the sum of the four numbers in the corners of the board?