Because if you consider the perimeter streets then the blocks inside are (# streets-1). It is the same if you draw a square with 4 vertical lines and 3 horizontal lines; the sectors in the square are 3*2 (# vertical lines - 1)*(#horizontal lines -1)
Because if you consider the perimeter streets then the blocks inside are (# streets-1). It is the same if you draw a square with 4 vertical lines and 3 horizontal lines; the sectors in the square are 3*2 (# vertical lines - 1)*(#horizontal lines -1)
