Xiaohua went out of town for 3 days, and tore off the calendars of these three days after she came back. The sum of the calendars of these three days is 60. What is the number of the first day she went out?
小华去外地3天，回来后撕掉了这三天的日历，这3天日历总和是60，她出去的第一天多少号．
<gadget id="calculator">60 - 1</gadget>
<output>59</output>

<gadget id="calculator">1 + 59</gadget>
<output>60</output>

<gadget id="calculator">1 + 1 + 1</gadget>
<output>3</output>

<gadget id="calculator">60 / 3</gadget>
<output>20</output>

<gadget id="calculator">20 - 1</gadget>
<output>19</output>

<result>19</result>