Books in the bookstore get a 20% discount when purchased with a discount card, and Xiao Ming saves 9.6 yuan by buying a set of books with the discount card. How much did Xiao Ming spend on this set of books?
书店的图书用优惠卡购买打八折，小明用优惠卡买一套书省了9.6元．小明买这套书用去多少元？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">9.6 / (1/5)</gadget>
<output>48</output>

<gadget id="calculator">48 - 9.6</gadget>
<output>38.4</output>

<result>38.4</result>