If a toy is sold at 80% of the original price, which is three yuan cheaper, what is the original price of this toy?
若一种玩具按原价的80%出售，便宜三元，则这种玩具原价为多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">3 / (1/5)</gadget>
<output>15</output>

<result>15</result>