Question

how many cubic blocks of side length 1/7 inch would it take to fill a cube with a side length of 3/7 inch?

Answer 1

Volume of the larger cube =(3/7)^3=27/343 cubic units

Volume of the small cubes=(1/7)^3=1/343 cubic units
Number of cubes=Volume of larger cube/Volume of small cubes
Number of cubes=(27/343) / (1/343)  cubes = 27/1 = 27