On the sports field, in the 400-meter hurdles competition, a hurdle is placed every 40 meters, and a hurdle is placed every 40 meters. How many hurdles can be placed on each track.
运动场上，在400米跨栏比赛中，每隔40米放一个栏架，每隔40米放一个栏架，每条跑道可放多少个栏架．
<gadget id="calculator">400 / 40</gadget>
<output>10</output>

<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<result>9</result>