First of all, the surface area in fifth grade mathematics refers to the surface area of a cuboid or cube. I looked it up a little, and I don't know if the landlord didn't say to solve the problem in different ways.

1) cubic surface area S= side length x side length X6

Cubic volume V= side length x side length x side length =(S/6)X side length

2) The surface area of a cuboid S= length× width X2+ length× height X2+ width× height X2.

Cuboid volume V= length × width × height

If we only know the surface area of a cuboid without any conditions, we can't get a definite value because there are too many unknowns.