Usage patterns
〈物〉と〈物〉の組み合わせa combination of X and Y
The combination of red and black looks stylish.
組み合わせが決まるfor a tournament matchup/pairing to be decided
Tomorrow's match pairings have been decided.
〈数〉通りの組み合わせa certain number of possible combinations
Let's calculate how many possible combinations there are for this problem.
組み合わせを考えるto think up a combination
I like coming up with combinations of dishes.