Xiaohua reads a children's story book and has read 36 pages, which is equivalent to (4/9) of the whole book. The number of pages he has read is the number of pages he has not read ((())/(())), the whole book How many pages are there?
小华看一本儿童故事书，已看了36页，相当于全书的(4/9)，已看的页数是没有看的页数的((())/(()))，全书有多少页．
<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">36 / (4/9)</gadget>
<output>81</output>

<result>81</result>