If a row of trees is planted between two buildings 80 meters apart, and one tree is planted every 5 meters, how many trees can be planted in total?
在相距80米的两楼之间栽一排树，每隔5米栽一棵树，共可栽多少棵树．
<gadget id="calculator">80 / 5</gadget>
<output>16</output>

<gadget id="calculator">16 - 1</gadget>
<output>15</output>

<result>15</result>