# Round-robin "by 2s" from legs A, B, C tickets: A+B, A+C, B+C # 3 parlays, equal stake each # Two of three legs winning still cashes one ticket; # a single 3-leg parlay would lose outright.
Round-robins don't change the expected value of the underlying legs - the book's margin per parlay still applies - they only reshape variance. The number of tickets grows combinatorially: 6 legs by 3s is already 20 parlays.
Pricing a round-robin is pure combinatorics on per-leg odds from the feed: enumerate the combinations, multiply decimal prices per ticket, and sum stakes. The parlay-math caveats - compounding vig, and correlation within a game - apply to every ticket.