A road is 200 meters long. The public security department decided to build a street lamp every 40 meters on both sides of the road (no need to plant at both ends). How many street lamps are needed in total?
一条公路长200米，公安部门决定在此公路两旁每隔40米建一盏路灯(两端不需要栽)，请问一共需要多少盏路灯？
<gadget id="calculator">200 / 40</gadget>
<output>5</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<result>8</result>