book has 200 pages. I read (1/2) on the first day, and (2/5) on the second day. How many pages did I read on the second day?
一本书有200页，第一天看了(1/2)，第二天看的是第一天的(2/5)，第二天看了多少页？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">200 * (1/2) * (2/5)</gadget>
<output>40</output>

<result>40</result>