In the new semester, the teachers distribute books to the students. After some have been distributed, those that have been distributed account for 1/4 of those that have not yet been distributed. After publishing 9 more books, those that have been published account for 2/3 of those that have not yet been published. How many books does the teacher have to distribute in total?
新学期，老师们给同学发书，发完一些后，已发的占未发的(1/4)．又发了9本后，已发的占未发的(2/3)．老师一共要发多少本书．
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + 4</gadget>
<output>5</output>

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

<gadget id="calculator">(2/5) - (1/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">9 / (1/5)</gadget>
<output>45</output>

<result>45</result>