**Answer – 1 (certain)** \n\nIn a standard 52?card deck every card is unique. \nWhen you draw five cards *without replacement*， you can never draw the same card twice. \nTherefore the probability that the first five cards are all distinct is\n\n\\[\nP(\\text{all 5 distinct}) = 1 .\n\\]\n\n*(If the question had meant “all 5 cards have different ranks” the probability would be \n\\(\\displaystyle \\frac{\\binom{13}{5}\\，4^5}{\\binom{52}{5}}\\approx 0.507\\).)*。