Probability of a flush in poker (5 cards of same suit)?

Probability of a flush in poker (5 cards of same suit)?

Approach: 4 * (13 choose 5) / (52 choose 5).

approx 0.00198. Favorable: 4 suits * 1287. Total: 2,598,960.

Follow-up: What is the probability of a straight flush?

Key concepts: combinations.