A book has 80 pages, the nickname is read on the first day (1/5), how many pages should be read on the second day.
一本书80页，小名第一天看了(1/5)，第二天应从多少页看起．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">80 * (1/5)</gadget>
<output>16</output>

<gadget id="calculator">16 + 1</gadget>
<output>17</output>

<result>17</result>