The original price of a hat is 18 yuan, and now the price is reduced by 10%. What is the current price of this hat?
一顶帽子原价18元，现在降价10%，这顶帽子现价多少元．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">18 * (9/10)</gadget>
<output>81/5 = around 16.2</output>

<result>81/5 = around 16.2</result>