You have 12 pennies in your pocket. Of those pennies, 3 are Canadian. Suppose you pick a penny out of your pocket at random. Find P(not Canadian).
There are a total of 12 pennies in your pocket, so the probability of picking any specific penny is 1/12.
Since 3 of the pennies are Canadian, the probability of picking a Canadian penny is 3/12 = 1/4.
Therefore, the probability of picking a penny that is not Canadian (P(not Canadian)) is 1 - P(Canadian) = 1 - 1/4 = 3/4.