glass of fruit juice, drank (2/5), how much is left in the glass?
一杯果汁，喝了(2/5)，杯中还有几分之几？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>