For a book, Qiqi read 30% of the whole book on the first day, the remaining 60% on the second day, and how much of the whole book he read on the second day.
一本书，奇奇第一天看了全书的30%，第二天看了剩下的60%，第二天看的是全书的多少．
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (3/10)</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(7/10) * (3/5)</gadget>
<output>21/50 = around 0.42</output>

<result>21/50 = around 0.42</result>