Im not sure how they get the 1287 and 2,598,960

EXAMPLE 7 Finding Probabilities Find the probability of being dealt 5 diamonds from a standard deck of 52 playing cards. SOLUTION ' In a standard deck of playing cards. 13 cards are diamonds. Note that it does not matter what order the cards are selected. The possible number of ways of choosing 5 diamonds out of 13 is 1305. The number of possible fivecard hands is 5205. So, the probability of being dealt 5 diamonds is P(5 diamonds) = \"05 = 1287 2,598,960 % 0.0005