The original price of a commodity is 90 yuan, the price is reduced by 10% first, and then the price is increased by 10%. What is the current price.
一种商品原价90元，先降价10%销售，后又上涨了10%销售．现价是多少元．
<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">1 + (1/10)</gadget>
<output>11/10 = around 1.1</output>

<gadget id="calculator">90 * (9/10) * (11/10)</gadget>
<output>891/10 = around 89.1</output>

<result>891/10 = around 89.1</result>