The store sells a mobile phone with an original price of 520 yuan. Now it is sold at a 10% discount. How much is the current price cheaper than the original price?
商店出售一种手机，原价520元，现在打九折出售，现价比原价便宜了多少元？
<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">520 * (1/10)</gadget>
<output>52</output>

<result>52</result>