Mix a kind of medicinal powder and water according to the ratio of 1:999 to make a potion. How many kg of powder is needed to prepare 200 kg of this liquid medicine?
把一种药粉和水按1：999配成药水．要配制这种药水200kg，需要药粉多少kg．
<gadget id="calculator">1 + 999</gadget>
<output>1_000</output>

<gadget id="calculator">1 / 1_000</gadget>
<output>1/1_000 = around 0.001</output>

<gadget id="calculator">200 * (1/1_000)</gadget>
<output>1/5 = around 0.2</output>

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