A piece of chocolate, Xiaodong ate (1/5), Xiaoli ate (2/5), how much is left?
一块巧克力，小东吃了(1/5)，小丽吃了(2/5)，还剩下几分之几？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(3/5) - (2/5)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>