For a novel, Xiao Ming read (1/3) of the whole book on the first day, and (2/9) of the whole book on the second day, and left more or less of the whole book.
一本小说，小明第一天看了全书的(1/3)，第二天看了全书的(2/9)，还剩下全书的多少没看．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">1 - (1/3) - (2/9)</gadget>
<output>4/9 = around 0.444444</output>

<result>4/9 = around 0.444444</result>