(1/2)*(1/5)/(1/2)*(1/5)=how much.
(1/2)*(1/5)/(1/2)*(1/5)=多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">(1/2) * (2/5) * (1/5)</gadget>
<output>1/25 = around 0.04</output>

<result>1/25 = around 0.04</result>