Reading an extra-curricular book, I read (1/6) of the whole book on the first day, and (1/5) of the whole book on the second day, leaving 19 pages unread. How many pages does this book have?
看一本课外书，第一天看了全书的(1/6)，第二天看了全书的(1/5)，还剩下19页没有看．这本书共有多少页？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

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

<gadget id="calculator">1 - (1/6) - (1/5)</gadget>
<output>19/30 = around 0.633333</output>

<gadget id="calculator">19 / (19/30)</gadget>
<output>30</output>

<result>30</result>