The probability of rolling a single 2 on a standard six-sided die is 1/6, as there are six possible outcomes and they are equally likely. The probability of rolling two 2s in a row is 1/36, which is calculated by taking the probability of the first roll being a 2 (1/6) and multiplying it by the probability of the second roll also being a 2 (1/6), as the two rolls are independent events. This use of multiplying the individual probabilities to determine the probability of multiple independent events follows the binomial distribution formula.