The purchase price of a coat is 90 yuan, the selling price is marked as 120 yuan, and then sold at 90% so how much profit can be made from it.
一件上衣进价90元，售价标为120元，然后按90%出售这样从中获利多少．
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">120 * (9/10)</gadget>
<output>108</output>

<gadget id="calculator">108 - 90</gadget>
<output>18</output>

<gadget id="calculator">18 / 90</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>