Xiaoqiang reads a book. He reads (1/4) of the whole book on the first day and the remaining 20% on the second day. He reads a total of 120 pages. How many pages are there in this book?
小强看一本书，第一天看了全书的(1/4)，第二天看了余下的20%，一共看了120页．这本书一共多少页．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(3/4) * (1/5)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(1/4) + (3/20)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">120 / (2/5)</gadget>
<output>300</output>

<result>300</result>