Xiao Ming reads a story book. He reads (1/5) on the first day and (1/4) on the second day. He read a total of 90 pages in two days. How many pages does this storybook have?
小明读一本故事书，第一天读了(1/5)，第二天读了(1/4)，两天一共读了90页．这本故事书有多少页？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">(1/5) + (1/4)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">90 / (9/20)</gadget>
<output>200</output>

<result>200</result>