A product with an original price of 100 yuan is now sold at a 20% discount. What is the actual price?
原价100元的商品，现在八折出售，实际售价是多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">100 * (4/5)</gadget>
<output>80</output>

<result>80</result>