A story book, student Xiao Hua read the whole book (3/8) in the first week, and the remaining 25% in the second week, leaving 150 pages unread. How many pages does this storybook have?
一本故事书，小花同学第一周看了全书的(3/8)，第二周看了余下的25%，还剩150页没有看．这本故事书共有多少页？
<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (3/8) - (1/4)</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">150 / (3/8)</gadget>
<output>400</output>

<result>400</result>