Remark
There must be 12 such boxes. Each one has a volume of 4 * 4 * 4 = 64 in^3
Proportion
1 box is 64 in^3
12 boxes = x
1/12 = 64/x Cross multiply
x = 12 * 64
x = 768 in^3
Note: We are not concerned with how to stack these boxes. We only want to know the volume.