calculate the probability of the following:

A four, three, or spade from a single draw from a 52 card deck.

there are 4 4's so 4/52, 4 3's so 4/52 and then 13/52 spades so 21/52 but and one 4 and one 3 are from spades so minus 2 = 19/52

Is this correct?

right.