A 300-page story book, I read (1/5) of the whole book on the first day and (1/4) of the whole book on the second day, how many pages are left?
一本300页的故事书，明明第一天看了全书的(1/5)，第二天看了全书的(1/4)，还剩多少页没有看？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/5) - (1/4)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">300 * (11/20)</gadget>
<output>165</output>

<result>165</result>