On Children's Day, Teacher Li spent 21.6 yuan to buy 6 popular textbooks for undergraduates in this class. How much is each book?
"六一"儿童节李老师花了21.6元买了6本科普读物送给本班困难的学生，每本书多少元？
<gadget id="calculator">21.6 / 6</gadget>
<output>3.6</output>

<result>3.6</result>