How do you do it

Question

A laptop computer is 59 mm thick. The packing box for the

laptop is 12.8 cm deep. If the packing material fills up the

space between the computer and the box, how thick is the

packing material?

Answer 1

12.8 cm = 128 mm

128 mm - 59mm = 69 mm = 6.9 cm thick

or 12.8 cm - 5.9 cm = 6.9 cm

Unless maybe you mean the computer is centered in the box, so the packing material's thickness is 6.9/2 = 3.45 cm on each side of the computer. Even if not centered, the average thickness would be 3.45 cm