Aunt Zhang bought a sweater and paid 180 yuan after a 10% discount. What was the original price of the sweater?
张阿姨买了一件羊毛衫，打九折后付款180元，这件羊毛衫的原价是多少？
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">180 / (9/10)</gadget>
<output>200</output>

<result>200</result>