If a pesticide is made into a potion at a ratio of 1:2000, how many grams of this pesticide should be added to 3000 grams of water?
把一种农药按照1：2000配成药水，在3000克的水中应加入这种农药多少克？
<gadget id="calculator">1 / 2_000</gadget>
<output>1/2_000 = around 0.0005</output>

<gadget id="calculator">3_000 * (1/2_000)</gadget>
<output>3/2 = around 1.5</output>

<result>3/2 = around 1.5</result>