The current price of a book is cheaper than the original price (1/6), and the original price is 4 yuan more than the current price. How much is the current price?
一本书现价比原价便宜了(1/6)，原价比现价贵4元，现价的多少元？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">4 / (1/6)</gadget>
<output>24</output>

<gadget id="calculator">24 - 4</gadget>
<output>20</output>

<result>20</result>