(1/4): (1/8) = x: (1/10).
(1/4)：(1/8)=x：(1/10)．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/4) * (1/10)</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/40) / (1/8)</gadget>
<output>1/5 = around 0.2</output>

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