The thickness of a kind of book is 25 mm, how many centimeters are stacked of 8 such books?
一种书的厚度是25毫米，8本这样的书摞起来厚多少厘米．
<gadget id="calculator">8 / 10</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">25 * (4/5)</gadget>
<output>20</output>

<result>20</result>