Yang Yang is reading a book. In the first month, he read 90 pages, and then read the whole book (1/4), exactly half of the book. How many pages does this book have?
阳阳正在读一本书，第一个月读了90页，再读全书的(1/4)，正好读了这本书的一半．这本书一共有多少页？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/2) - (1/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">90 / (1/4)</gadget>
<output>360</output>

<result>360</result>