Probability Theory

In the probability theory,  every possible event has a non-negative number between 1 and 0.

For two random events to happen, like for 0.3 for stock market to go down and 0.6 for it to rain, it is 0.3 x 0.6 = 0.18

Therefore, if you want to know two exclusive events happening for the stock market to go up, like a clown striding into the room(0.0004102) and the lights going out for 1 second(0.000032).

Add them up to find out. 0.0004102 + 0.000032 = 0.0004422