Xiaohua planned to read a book in four days, but he read the whole book on the first day (2/9). He read (1/6) of the whole book on the second day and (1/4) of the whole book on the third day, so what fraction of the whole book should Xiaohua read on the fourth day?
小华计划四天看完一本书，第一天看了全书的(2/9)．第二天看了全书的(1/6)，第三天看了全书的(1/4)，那么小华第四天应看完全书的几分之几？
<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (2/9) - (1/6) - (1/4)</gadget>
<output>13/36 = around 0.361111</output>

<result>13/36 = around 0.361111</result>