Starting from 12, count every 5. Count to 87. How many numbers did you count in total?
从12开始，每隔5数一个数．一直数到87．一共数了多少个数？
<gadget id="calculator">87 - 12</gadget>
<output>75</output>

<gadget id="calculator">75 / 5</gadget>
<output>15</output>

<result>15</result>