How many 1-inch cubes will fit into a 3 and 1/2 in rectangular prism?

Suppose the height of the prism is 1 in, then the volume will be:
volume=length×width×height
thus
volume of the prism will be:
V=3×1/2×1
V=1.5 in³

Volume of the cube will be:
v=1×1×1=1 in³
Thus the number of cubes that will be in the prism will be:
(1.5 in³)/(1 in³)
=1.5 cubes~2 cubes

Its d so thats how it would would back from 1.0 form three four two