C(n, k) = n! / (k!(n-k)!)

where n is the total number of items (in this case, 22), k is the number of items to choose (in this case, 11), and ! denotes the factorial function (e.g., 5! = 5 × 4 × 3 × 2 × 1).

Plugging in the values, we get:

C(22, 11) = 22! / (11!(22-11)!)
= 22! / (11!11!)
= 705,432

So, there are 705,432 unique combinations of 11 numbers that can be formed from 1 to 22.

Keep in mind that this calculation assumes that the order of the numbers doesn't matter. If the order matters, then we're dealing with permutations, and the calculation would be different.