Read a 300-page book, read (1/4) on the first day, and the rest of the book (2/5) on the second day, how many pages did you read the next day?
看一本300页的书，第一天看了(1/4)，第二天看完还剩下全书的(2/5)，第二天看了多少页？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">1 - (2/5) - (1/4)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">300 * (7/20)</gadget>
<output>105</output>

<result>105</result>