Xiaodong reads a story book. On the first day, he reads 2/5 of the whole book, and on the second day, he reads 30% of the whole book. There are 45 pages left. How many pages does this book have?
小东看一本故事书，第一天看全书的(2/5)，第二天看全书的30%，还剩下45页，这本书有多少页？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (2/5) - (3/10)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">45 / (3/10)</gadget>
<output>150</output>

<result>150</result>