Answer:
400%.
Explanation:
The surface area of a 4 cm cube = 6 * 4^2
= 96 cm^2.
The number of 1 cm cubes that can be cut from the larger cube is :
16 * 4 = 64.
The surface area of each of these smaller cubes is 6*1 = 6 cm^2.
The increase in surface area is a factor of (6*64) / 96
= 4 = 400%.