If you toss two dice and add the numbers facing up, what is the probability that the sum of the dice equals 5 or the sum of the dice is even?

There are 6*6=36 possible outcomes for a two-die throw.
There are 4 ways to throw a 5 {(1,4),(2,3),(3,2),(4,1)}.
So the probability is P(4)=5/36.
There are 18 ways to throw an even number.
So P(even)=18/36=1/2