Hi Miss, to find the probability of the card being either a space or a four, start by find the probability of getting a spade. Then, find the probability of getting a four. Last, add the two probabilities to get the final probability.
P(a spade) = 13/52, or 1/4, since there are 13 spades in a standard deck.
p(a four) = 4/52, or 1/13, since there are 4 fours in a standard deck.
p(a spade or a four) = 1/4 + 1/13, which is equal to: 13/52 + 4/52 = 17/52
Note: the common denominator for 4 and 13 is 52, we could have eliminated the steps to reduce both fractions.