A book has 40 pages. Xiao Ming reads (1/8) on the first day and (3/8) on the second day. What percentage of the book did he read? How many pages are left?
一本书有40页，小明第一天看了(1/8)，第二天看了(3/8)，他一共看了几分之几？还剩多少页没看？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">40 * (1/2)</gadget>
<output>20</output>

<result>20</result>