This year's summer vacation starts on July 10th, and classes officially begin on September 1st. How many days are there in this summer vacation?
今年暑假从7月10日开始，9月1日正式开始上课．这个暑假一共有多少天．
<gadget id="calculator">31 - 10</gadget>
<output>21</output>

<gadget id="calculator">21 + 1 + 31</gadget>
<output>53</output>

<result>53</result>