The original price of a shirt is 40 yuan. If it is sold at a 10% discount, how much is the price?
一件衬衣的原价是40元，如果以九折出售，售价是多少元．
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">40 * (9/10)</gadget>
<output>36</output>

<result>36</result>