For a potion containing 10% medicine, the weight of the water is much more than the weight of the medicine.
含药10%的药水，水的重量比药的重量多多少．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10) - (1/10)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) / (1/10)</gadget>
<output>8</output>

<result>8</result>