There are 45 books in the school library. After some of them have been borrowed, there are still (2/9) left. How many books should be borrowed?
学校图书室有45本图书，借出一部分后，还剩(2/9)，借出几本图书？
<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">1 - (2/9)</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">45 * (7/9)</gadget>
<output>35</output>

<result>35</result>