Xiaolan reads a story book. If she reads 25 pages a day, she will finish it 2 days later than planned; if she reads 30 pages a day, she will finish it 1 day earlier than planned. How many pages does the book have in total?
小兰看一本故事书，如果每天看25页，比计划推迟2天看完；如果每天看30页，则比计划提前1天看完，那么这本书一共有多少页？
<gadget id="calculator">25 * 2</gadget>
<output>50</output>

<gadget id="calculator">30 + 50</gadget>
<output>80</output>

<gadget id="calculator">30 - 25</gadget>
<output>5</output>

<gadget id="calculator">80 / 5</gadget>
<output>16</output>

<gadget id="calculator">16 + 2</gadget>
<output>18</output>

<gadget id="calculator">25 * 18</gadget>
<output>450</output>

<result>450</result>