In a story book, the ratio of the number of pages you have read to the number of pages you have not read is 2:3. If you read another 70 pages, you will just read the complete book (3/4). How many pages does this book have?
一本故事书，已看的页数和没看的页数比是2：3，再看70页，正好看完全书的(3/4)，这本书有多少页？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(3/4) - (2/5)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">70 / (7/20)</gadget>
<output>200</output>

<result>200</result>