There are 4 classes in the third grade of Zhenxing Primary School, and each class has 42 students. If everyone borrows 3 books from the library, how many books are borrowed by students in this grade?
振兴小学三年级有4个班，每班都是42人．如果每人都从图书馆借3本书，这个年级的学生一共借书多少本？
<gadget id="calculator">42 * 4 * 3</gadget>
<output>504</output>

<result>504</result>