Wang Hao reads a 40-page story book. He reads (1/6) of this book on the first day and (2/6) of this book on the second day. How much of this book is left did not read.
王浩看一本40页的故事书，他第一天看了这本书的(1/6)，第二天看了这本书的(2/6)，还剩下这本书的多少没有看．
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">2 / 6</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/6) - (1/3)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>