There is a suit in the "Suit Counter". It used to be 900 yuan per set. The merchants held promotional activities on New Year's Day. Now each set is sold at a 10% discount. How much is it cheaper to buy such a suit now?
"西装专柜"有一款西服，原来每套900元，商家庆元旦搞促销活动，现在每套九折出售，现在买这样一套西服便宜多少元？
<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">900 * (1/10)</gadget>
<output>90</output>

<result>90</result>