Yesterday and today, the school cafeteria bought the same amount of vegetables and meat. Yesterday I paid 250 yuan, and today I paid 280 yuan. The reason is that the price of vegetables increased by 10%, and the price of meat increased by 20%. So, how much did you pay for vegetables today?
昨天和今天，学校食堂买了同样多的蔬菜和肉，昨天付了250元，今天付了280元，原因是蔬菜涨价10%，肉涨价20%，那么，今天蔬菜付了多少元．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) * 250</gadget>
<output>50</output>

<gadget id="calculator">50 - 280</gadget>
<output>-230</output>

<gadget id="calculator">250 + (-230)</gadget>
<output>20</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/5) - 1 - (1/10)</gadget>
<output>-9/10 = around -0.9</output>

<gadget id="calculator">1 + (-9/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">20 / (1/10)</gadget>
<output>200</output>

<gadget id="calculator">1 + (1/10)</gadget>
<output>11/10 = around 1.1</output>

<gadget id="calculator">200 * (11/10)</gadget>
<output>220</output>

<result>220</result>