volume of rectangular prism is first edge*second edge*third edge (product of
prism dimensions)
1st edge has 4 small cubes , edge of the small cube=1/4,
so 1st edge of the large cube =1/4*4=4/4 (it could be written as 1)
2d edge has 3 small cubes , so 2d edge= 3*1/4=3/4
3d edge has also 3 small cubes , so 3d edge= 3*1/4=3/4
Volume= first edge*second edge*third edge=4/4*3/4*3/4=1*3/4*3/4=9/16
Answer 4/4*3/4*3/4=9/16