A book with 150 pages, if you read 20% on the first day, what page should you start reading on the second day?
一本书150页，第一天读了20%，第二天应从第多少页读起．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">150 * (1/5)</gadget>
<output>30</output>

<gadget id="calculator">30 + 1</gadget>
<output>31</output>

<result>31</result>