A story book, Xiaoling read the whole book (1/5) on the first day, read 21 pages on the second day, and left 47 pages unread. How many pages does this book have?
一本故事书，小玲第一天读了全书的(1/5)，第二天读了21页，还有47页没有读．这本书一共有多少页？
<gadget id="calculator">21 + 47</gadget>
<output>68</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">68 / (4/5)</gadget>
<output>85</output>

<result>85</result>