The distance between every two electric poles is 50 meters. How many meters did Xiaoqiang run from the first electric pole to the ninth electric pole?
每两根电杆间的距离是50米，小强从第一根电杆跑到第9根电杆，共跑了多少米米．
<gadget id="calculator">9 - 1</gadget>
<output>8</output>

<gadget id="calculator">50 * 8</gadget>
<output>400</output>

<result>400</result>