0.5 kg of salt is dissolved in 20 kg of water, what is the weight of the salt in the salt water
0、5千克盐溶解在20千克水中，盐的重量占盐水的多少
<gadget id="calculator">0.5 + 20</gadget>
<output>20.5</output>

<gadget id="calculator">0.5 / 20.5</gadget>
<output>0.02439</output>

<result>0.02439</result>