National Day promotion, all books are sold at half price, Xiaoling bought "Fun Mathematics" for 15 yuan, how much is the original price of "Fun Mathematics"? (solution by equation)
国庆节促销，所有的书籍一律半价出售，小玲花15元买了本《趣味数学》，《趣味数学》原价是多少元？(用方程解)
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">15 / (1/2)</gadget>
<output>30</output>

<result>30</result>