Xiaohong reads "Gulliver's Travels", and has read (4/5) of the whole book. The part she has not read is the part she has read.
小红看一本《格列佛游记》，已看了全书的(4/5)，未看的部分是已看部分的多少．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) / (4/5)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>