If two dice are rolled one time, find the probability of getting a sum of 4

There are six faces for each of two dice, giving 36 possible outcomes. If the two dice are fair, each of 36 outcomes is equally likely. Three outcomes sum to 4: (1+3), (2+2) and (3+1). Probability of getting a sum of 4 on one toss of two dice is 3/36, or 1/12.