Campus Art Festival, from October 9th to October 16th, how many days are there in total?
校园艺术节，从10月9日开始到10月16日结束，一共有多少天．
<gadget id="calculator">16 - 9</gadget>
<output>7</output>

<gadget id="calculator">7 + 1</gadget>
<output>8</output>

<result>8</result>