College Street is 500 meters long, and a garbage bin is placed every 25 meters, at both ends. How many garbage bins are needed?
学院街长500米，每隔25米放一个垃圾箱，两端都放，需要垃圾箱多少个？
<gadget id="calculator">500 / 25</gadget>
<output>20</output>

<gadget id="calculator">20 + 1</gadget>
<output>21</output>

<result>21</result>