The current price of a commodity is 75% of the original price, how much cheaper the current price is than the original price.
一种商品现价是原价的75%，现价比原价便宜了多少．
<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>