Put 20 grams of sugar into 100 grams of water. After three days, the weight of the sugar water is only 100 grams. At this time, the concentration of the sugar water has increased compared to the concentration three days ago.
20克糖放入100克水中，放置三天后糖水重量只有100克，这时糖水的浓度比三天前的浓度提高了多少．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">100 + 20</gadget>
<output>120</output>

<gadget id="calculator">20 / 120</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/5) - (1/6)</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/30) / (1/6)</gadget>
<output>1/5 = around 0.2</output>

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