There is a 60-meter-long trail in the campus. It is necessary to plant a tree every 5 meters on both sides of the trail.
校园内有一条60米长的小道，要在小道的两旁每隔5米植一棵树，首尾都要植，一共要准备多少棵树苗．
<gadget id="calculator">60 / 5</gadget>
<output>12</output>

<gadget id="calculator">12 + 1</gadget>
<output>13</output>

<gadget id="calculator">13 * 2</gadget>
<output>26</output>

<result>26</result>