The new semester is about to start, and the school playground is neatly stacked with student textbooks. There are 6 boxes in a row, and 9 rows are a floor. There are 4 floors like this. How many boxes are there in total?
新学期要开始了，学校操场上整齐的码放着学生课本，一排有6箱，9排是一层，有这样的4层，一共有多少箱？
<gadget id="calculator">6 * 9 * 4</gadget>
<output>216</output>

<result>216</result>