Plant trees beside a 100-meter-long path, how many trees should be planted at intervals of 5 meters (both ends are planted).
在一条100米长小路一旁种树，每隔5米种一棵(两端都种)共要种多少棵．
<gadget id="calculator">100 / 5</gadget>
<output>20</output>

<gadget id="calculator">20 + 1</gadget>
<output>21</output>

<result>21</result>