P(2 or H) = P(2) + P(H) - P(2 and H)
What is the probability of getting a 2 P(2)? = 1/6
What is the probability of getting heads P(H)? = 1/2
P(2 and H) is the product of those two events since the events are independent. = 1/6 * 1/2 = 1/12
P(2 or H) = P(2) + P(H) - P(2 and H)
P(2 or H) = 1/6 + 1/2 - 1/12 = 7/12