It takes 500 yuan to pave the classroom with square bricks with a side length of 40 cm. If the floor is paved with square bricks with a side length of 50 cm, how many pieces can be saved?
用边长是40厘米的方砖给教室铺地需500块，如果改用边长是50厘米的方砖铺地，可节省多少块？
<gadget id="calculator">40 * 40 * 500</gadget>
<output>800_000</output>

<gadget id="calculator">50 * 50</gadget>
<output>2_500</output>

<gadget id="calculator">800_000 / 2_500</gadget>
<output>320</output>

<gadget id="calculator">500 - 320</gadget>
<output>180</output>

<result>180</result>