There are 36 possible outcomes when rolling two dice, since each die has 6 possible outcomes.
To find the probability of rolling a sum of 3, we need to count the number of ways we can roll a sum of 3 and divide by the total number of possible outcomes.
The only ways to get a sum of 3 are by rolling a 1 on the first die and a 2 on the second die, or vice versa. There is only one way to roll each of these outcomes. Therefore, there are 2 ways to roll a sum of 3.
So the probability of rolling a sum of 3 is:
Probability of rolling a sum of 3 = Number of ways to roll a sum of 3 / Total number of possible outcomes
Probability of rolling a sum of 3 = 2 / 36
Probability of rolling a sum of 3 = 1 / 18
Therefore, the probability of rolling a sum of 3 with a pair of standard dice is 1/18 or approximately 0.056.