A story book, I read (2/3), what I didn't read is the number of pages I read.
一本故事书，看了(2/3)，没看的是看的页数的多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

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

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