There is 50 meters between two telephone poles, and a tree is planted every 10 meters between them. How many trees can be planted in total?
两根电线杆之间有50米，它们之间每隔10米种一棵树，一共能种多少棵树．
<gadget id="calculator">50 / 10</gadget>
<output>5</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<result>4</result>