When Xiao Ming reads a book, he reads (1/3) of the whole book on the first day, and reads 30 pages on the second day. At this time, the number of pages not read is (1/3). How many pages does this book have?
小明读一本书，第一天读了全书的(1/3)，第二天读了30页，这时，没有读的页数是读了的(1/3)．这本书有多少页？
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(3/4) - (1/3)</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">30 / (5/12)</gadget>
<output>72</output>

<result>72</result>