The current price of a pen is 16 yuan, which is the original price (4/5). How much is the original price of this pen?
一支钢笔现价16元，是原价的(4/5)，这支钢笔的原价是多少元？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">16 / (4/5)</gadget>
<output>20</output>

<result>20</result>