On a strip of paper 80 cm long, make a mark every 5 cm, how many marks should be made in total.
在一条长80厘米的纸条上，每隔5厘米做一个记号，一共要做多少个记号．
<gadget id="calculator">80 / 5</gadget>
<output>16</output>

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

<result>15</result>