A book has 200 pages in total. Xiao Ming has read 40% of the book. How many pages does Xiao Ming read?
一本书共200页，小明已经看了全书的40%，小明看了多少页．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">200 * (2/5)</gadget>
<output>80</output>

<result>80</result>