In a glass of sugar water, sugar accounts for (1/10) of the sugar water, and then 10 grams of sugar is added, and the sugar accounts for (1/5) of the water. How many grams of sugar are there in this glass of sugar water?
一杯糖水，原来糖占糖水的(1/10)，后来又加入10克糖，这时糖占水的(1/5)，原来这杯糖水中有糖多少克？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) * 9</gadget>
<output>9/5 = around 1.8</output>

<gadget id="calculator">(9/5) - 1</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">10 / (4/5)</gadget>
<output>25/2 = around 12.5</output>

<result>25/2 = around 12.5</result>