This is the addition rule for 3 events.

Here is an example and a diagram:

P(A)=.20, P(B)=.50, P(C)=.30, P(A and B)=.15, P(A and C)=.13

P(B and C)=.20, P(A and B and C)=.10

You can use the formula to get .62

From the diagram you can see the respective events.