If it is a rectangle, if the width is x, then the length is X+2, and the reduced area is 2X=48.

So X=24.

So the original rectangular area is 24*26=624 square centimeters.

If it is a cuboid, assuming the original width is x, then the length is X+2, the height is x, and the reduced area is 4X*2=48, then X=6.

Then the volume of the original cuboid is 6*6*8=288 cubic centimeters.

If you tell it to primary school students, you'd better bring a picture to explain it.