Teacher Zhang borrowed a book, read 30% of the book on the first day, and read 2/3 of the first day (2/3) on the second day, and read a total of 70 pages in two days. How many pages does this book have?
张老师借来一本书，第一天看了全书的30%，第二天看的是第一天的(2/3)，两天共看了70页，这本书共有多少页？
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(3/10) * (2/3)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(3/10) + (1/5)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">70 / (1/2)</gadget>
<output>140</output>

<result>140</result>