The school bought 690 books and distributed them to 3 grades on average. Each grade has 5 classes. How many books are distributed to each class on average?
学校买来690本书，平均分给3个年级，每个年级有5个班级，平均每个班级分到多少本？
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">690 / 15</gadget>
<output>46</output>

<result>46</result>