Xiao Ming reads a book. He reads the whole book (3/10) on the first day, and reads 10 pages on the second day. He reads the whole book (2/5) in two days. How many pages are there in total?
小明读一本书，第一天读了全书的(3/10)，第二天读了10页，两天共读了全书的(2/5)，求全书共多少页？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(2/5) - (3/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">10 / (1/10)</gadget>
<output>100</output>

<result>100</result>