Xiao Ming reads a book, he reads it on the first day (1/9), and the second day (2/9), how much is left.
小明看一本书，第一天看了(1/9)，第二天看了(2/9)，还剩多少没有看．
<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">(1/9) + (2/9)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<result>2/3 = around 0.666667</result>