Two big red flags have been planted at both ends of the 100-meter-long runway, and the teacher asked them to line up with small colored flags at intervals of 5 meters.
在100米长的跑道两端已经插了两面大红旗，老师要求每间隔5米再插队上小彩旗，共插小彩旗多少面．
<gadget id="calculator">100 / 5</gadget>
<output>20</output>

<gadget id="calculator">20 - 1</gadget>
<output>19</output>

<result>19</result>