(3/10): (1/5)=(1/4): Χ.
(3/10)：(1/5)=(1/4)：Χ．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/5) * (1/4)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(1/20) / (3/10)</gadget>
<output>1/6 = around 0.166667</output>

<result>1/6 = around 0.166667</result>