grams and 18 grams of water are mixed together to make salt water, what is the percentage concentration of salt water
2克和18克水混合在一起配成盐水，则盐水的百分比浓度是多少
<gadget id="calculator">2 + 18</gadget>
<output>20</output>

<gadget id="calculator">2 / 20</gadget>
<output>1/10 = around 0.1</output>

<result>1/10 = around 0.1</result>