A sweater is sold in a shopping mall, and it is 50 yuan cheaper after a 10% discount. How much is the original price of this sweater?
商场出售一件毛衣，打九折后便宜了50元，这件毛衣原价多少元？
<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">50 / (1/10)</gadget>
<output>500</output>

<result>500</result>