A disinfectant solution, the ratio of medicine to water is 1:19, what is the concentration of the medicine solution.
一种消毒液，药与水的比是1：19，药液的浓度为多少．
<gadget id="calculator">1 + 19</gadget>
<output>20</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

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

<result>1/20 = around 0.05</result>