Xiao Ming reads a book of 60 pages, and has read 39 pages, and has not read the rest of the book.
小明看一本共60页的书，已经看了39页，还剩全书的多少没有看．
<gadget id="calculator">60 - 39</gadget>
<output>21</output>

<gadget id="calculator">21 / 60</gadget>
<output>7/20 = around 0.35</output>

<result>7/20 = around 0.35</result>