A circular runway is 400 meters long. If a warning sign is erected every 10 meters, how many warning signs are needed?
一个圆形跑道400米，如果每隔10米竖一块警示牌，共需要多少块警示牌．
<gadget id="calculator">400 / 10</gadget>
<output>40</output>

<result>40</result>