Solution ratio: ((3.2)/4)=((x-8)/5).
解比例：((3.2)/4)=((x-8)/5)．
<gadget id="calculator">3.2 / 4</gadget>
<output>0.8</output>

<gadget id="calculator">8 / 5</gadget>
<output>8/5 = around 1.6</output>

<gadget id="calculator">0.8 + (8/5)</gadget>
<output>2.4</output>

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

<gadget id="calculator">2.4 / (1/5)</gadget>
<output>12</output>

<result>12</result>