Answer:
9 blocks
Step-by-step:
One way in which to do this problem is to find the volume of the rectangular prism and then divide that by the volume of one cubic block of side length 1/6 inch.
V = (length)(width)(height) = (1/2 cm)(1/6 cm)(1/2 cm) = 1/24 cm³.
Volume of one cubic block of side length 1/6 cm is (1/6 cm)³ = 1/216 cm³.
Dividing 1/24 cm³ by 1/216 cm³ yields 216/24 blocks, or 9 blocks.