a gift box has dimensions of 8 1/2 inches 5 1/2 inches and 2 1/2 inches respectively how many cubes with side lengths of 1/2 inches would be needed to fill the gift box

Find the volume of each and then divide the volume of the box by the volume of the cube.
Volume of box: 8 1/2 x 5 1/2 x 2 1/2 = 116 7/8 cubic inches.
Volume of cube = 1/2^3 = 1/8 cubic inches
Number of cubes: 116 7/8 / 1/8 = 935 cubes.