A piece of chocolate, eat it (2/5), how much of it is left
一块巧克力，吃了它的(2/5)，还剩它的多少
<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>