How many utility poles are needed in total to erect utility poles on one side of a road with a length of 1 km, every 50 meters, and at both ends of the highway?
在一条长1千米的公路一侧架设电线杆，每隔50米架设一根，公路两端都要架，共需要多少根电线杆？
<gadget id="calculator">1_000 / 50</gadget>
<output>20</output>

<gadget id="calculator">1 * 20</gadget>
<output>20</output>

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

<result>21</result>