The price of a pair of shoes decreases by 20%, and then increases by 8 yuan, and the price at this time is 80 yuan. how much is the original price of these shoes
一种鞋子的价格下降20%后又增加了8元，这时的价格是80元．这种鞋子的原价是多少元
<gadget id="calculator">80 - 8</gadget>
<output>72</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">72 / (4/5)</gadget>
<output>90</output>

<result>90</result>