The original price of an MP3 is 500 yuan, and it is now on sale with a 30% discount. How much is the current price?
一个MP3原价500元，现打七折出售，现在售价多少元．
<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">500 * (7/10)</gadget>
<output>350</output>

<result>350</result>