Two big trees are 20 meters apart, and a Chinese rose is to be planted every 2 meters between the two big trees. How many Chinese roses should be planted in total?
两棵大树相距20米，要在这两棵大树之间每隔2米栽一棵月季花，一共要载多少棵月季花．
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<result>9</result>