There is a piece of cloth that has been used up (3/5), how much is left?
有一块布，用去了(3/5)，还剩下几分之几？
<gadget id="calculator">3 / 5</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>