60% of a book has been read, and there are still ((())/(())) not read.
一本书看了60%，还有((())/(()))没看．
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>