problem solving - chess board


How many squares are there on a chess board?

P.S. No, the answer is not 64

Explanation:

Of course, as you might think, aren’t there only 8 x 8 = 64 squares on a chess board? Well, no. All these 64 squares are squares of 1 block. However, one can notice that there are squares of 4 blocks too i.e., 7 x 7 = 49. Likewise, until the largest square which is the chess board itself.
1, 8x8 square
4, 7x7 squares
9, 6x6 squares
16, 5x5 squares
25, 4x4 squares
36, 3x3 squares
49, 2x2 squares
64, 1x1 squares

Thus, totally, there are 64 + 49 + 36 + 25 + 16 + 9 + 4 + 1 = 204 squares on a chess board.