A book, read 5% of the whole book, how much is left unread.
一本书，看了全书的5%，还剩多少没有看．
<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 - (1/20)</gadget>
<output>19/20 = around 0.95</output>

<result>19/20 = around 0.95</result>