The current price of a commodity is 78% of the original price, how much is the current price lower than the original price?
一种商品现价是原价的78%，现价比原价降低了多少．
<gadget id="calculator">78 / 100</gadget>
<output>39/50 = around 0.78</output>

<gadget id="calculator">1 - (39/50)</gadget>
<output>11/50 = around 0.22</output>

<result>11/50 = around 0.22</result>