Two dice are thrown. what is the probability that the sum of dots is 4 or 6?

Assuming that the two dice are thrown together (and thus the "order" that the dice are thrown/land don't matter), there are 21 total pairs of dice values that can occur. They are as follows:

We must now find how many of these pairs sum to 4 or 6. These are:

So the probability of rolling a sum of 4 or 6 is