Simply put, it says that the numbers can be added in any order, and you will still get the same answer. For example, if you are adding one and two together, thecommutative property<span> of addition says that you will get the same answer whether you are adding 1 + 2 or 2 + 1. This also works for more than two numbers.</span>
The formula of density is mass / volume. So, the volume is equal to the area of the cube by the total height, so the area of the cube is 3x3= 9, and this result multiplied by the height, 9x3 = 27. Following the formula of density, we have 216 g / 27 cm^3, the result is 8 g/cm^3. Hope you undestand my procedure XD
