In the first quarter of this year, Dad's rest days were less than his working days (8/13). How many days did he work in the first quarter?
今年第一季度，爸爸的休息日比工作日少(8/13)，第一季度工作了多少天．
<gadget id="calculator">8 / 13</gadget>
<output>8/13 = around 0.615385</output>

<gadget id="calculator">1 - (8/13)</gadget>
<output>5/13 = around 0.384615</output>

<gadget id="calculator">(5/13) + 1</gadget>
<output>18/13 = around 1.384615</output>

<gadget id="calculator">90 / (18/13)</gadget>
<output>65</output>

<result>65</result>