It takes 520 pieces to lay a square with a side length of 25 cm. Now, how many pieces of rectangular tiles with a side length of 20 cm and a width of 10 cm are needed to lay the same piece of land?
25 * 25 * 520 / 20 / 10 = 1652 pieces
25 * 25 * 520 / 20 / 10 = 1652 pieces