Teacher Zhang bought a reference book during the discount period of the education bookstore. The current price is 16 yuan, which is 20% cheaper than the original price. Ask: What is the original price?
张老师在教育书店打折期间买了一本参考书，现在的价钱是16元，比原价便宜了20%，问：原价是多少？
<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">16 / (4/5)</gadget>
<output>20</output>

<result>20</result>