A book has 80 pages in total. I read it on the first day (1/4). The ratio of the number of pages I read on the first day to the second day is 2:5. How many pages are left?
一本书共80页，第一天看了(1/4)，第一天和第二天看的页数比是2：5，还剩多少页没看？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">(1/4) * (5/2)</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">1 - (1/4) - (5/8)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">80 * (1/8)</gadget>
<output>10</output>

<result>10</result>