To calculate the oxidation numbers of Ca in CaF2, we assume that the fluorine atom (F) has an oxidation number of -1, as it is a halide. Let x represent the oxidation number of Ca.

The overall charge of the compound CaF2 must be neutral. Therefore, we can set up the following equation:

2x + 2(-1) = 0

Solving for x, we get:

2x - 2 = 0

2x = 2

x = +1

Therefore, the oxidation number of calcium (Ca) in CaF2 is +2.