A book has 250 pages in total. I read (2/5) of the whole book on the first day and (1/5) of the whole book on the second day. How many pages are left?
一本书共250页，第一天读了全书的(2/5)，第二天读了全书的(1/5)，还剩多少页没读？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">1 - (2/5) - (1/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">250 * (2/5)</gadget>
<output>100</output>

<result>100</result>