A commodity whose price is raised by 20% first, and then raised by 20% later, is now sold at the original price.
一种商品，先提价20%，后来又提价20%，现在的售价是原定价的多少．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(6/5) / 1</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(6/5) * (6/5)</gadget>
<output>36/25 = around 1.44</output>

<result>36/25 = around 1.44</result>