Teacher Li has 50 yuan and wants to buy 10 copies of "Popular Science Stories" at 4.52 yuan each. How much should Mr. Li get back?
李老师有50元钱，想买10本《科普故事》，每本4.52元．应找回李老师多少钱？
<gadget id="calculator">4.52 * 10</gadget>
<output>45.2</output>

<gadget id="calculator">50 - 45.2</gadget>
<output>4.8</output>

<result>4.8</result>