If a commodity is first reduced by 10% and then raised by 10% to buy 100 yuan, what is the original price of this commodity?
一种商品，先降价10%后，又涨价10%后买100元，这件商品的原价是多少？
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 + (1/10)</gadget>
<output>11/10 = around 1.1</output>

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

<gadget id="calculator">100 / (11/10) / (9/10)</gadget>
<output>10_000/99 = around 101.010101</output>

<result>10_000/99 = around 101.010101</result>