For a commodity, first increase the price (1/10), and then decrease the price (1/10), what fraction of the original price is the current price? How many
一件商品，先提价(1/10)，再降价(1/10)，那么现价是原价的几分之几？多少
<gadget id="calculator">1 / 10</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">(11/10) * (9/10)</gadget>
<output>99/100 = around 0.99</output>

<result>99/100 = around 0.99</result>