Answer:
2 1/2 cubic units
Step-by-step explanation:
It might help to change the dimensions into half-units (by doubling them).
Width 1 = 2 half-units
Length 1 1/2 = 3 half-units
Height 1 1/2 = 3 half-units
Multiply length x width x height = 18 half-unit cubes
But there are 8 half-unit cubes in every unit cube, so divide the 18 half-unit cubes by 8 to get 18 / 8 = 9/4 = 2 1/2 (two and a half) cubic units