The density of a substance is its mass divided by its volume:

d=m/V

Ice is less dense than liquid water so 1000 ml of liquid water, when frozen, will have a greater volume. (Note that the unit ml is equivalent to cm^3 or cc.)  

In order to solve this problem we need to know the density of water, which isn't given. Water's density varies slightly with temperature. The value often used is 1.00 g/cm^3 at a temperature of 25 degrees C. We'll use this value to solve the problem since temperature isn't given.

1. The mass of ice is equal to the mass of liquid water, which we can calculate as follows:

d = m/V, so m = d x V

m = (1.00 g/cm^3)(1000 cm^3) = 1.00 gram

2. Find the volume of 1.00 g ice:

V = m/d = (1.00g)/(0.91 g/cm^3) = 1.10 cm^3