The original price of a book is 18 yuan, and now it is sold at a 30% discount. How much is it selling now?
一本图书原价18元，现在打七折出售，现在卖多少元．
<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">18 * (7/10)</gadget>
<output>63/5 = around 12.6</output>

<result>63/5 = around 12.6</result>