Celebrating New Year's Day, there is a big price cut, and all home appliances in a shopping mall are sold at a 10% discount. The original price of an air conditioner is 2,800 yuan, how much cheaper is the current price.
庆元旦，大降价，某商场的家电一律九折出售，一台空调原价2800元，现价便宜了多少元．
<gadget id="calculator">90 / 100</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">2_800 * (1/10)</gadget>
<output>280</output>

<result>280</result>