The original price of a mobile phone is 600 yuan. Now it is sold at a 10% discount. What is the current price?
一种手机原价是600元，现在打九折出售，现价是多少元．
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">600 * (9/10)</gadget>
<output>540</output>

<result>540</result>