9 total.
4 1x1
2 1x2
2 2x1
1 2x2
There are 2025 rectangles in a 9x9 grid.
That depends on how big the rectangles are.
In a 4 by 4 grid, there are 16 squares (1x1 squares), 9 rectangles that are 2x1, 6 rectangles that are 3x1, 4 rectangles that are 2x2, and 1 rectangle that is 4x4. Therefore, in total, there are 16 squares and 20 rectangles in a 4 by 4 grid.
5
96 rectangles.
441
4 rectangles
225
62 x 38 = 2356 rectangles
14
90
9