How do i determine how many possibilities there are here?

i have this: https://imgur.com/a/N5sIfgD

i need to figure out how many combinations there are if the black dots have a 1/2 chance of being red and a 1/2 chance of being black, how would I solve this?

Take how many dots there are, in this case 25 (5 * 5,) multiply that by 2, which gives you 50 possible combinations.

I think I did that right???

use X.

local X = math.random(1,2)
if X == 1 then
	--black dots
end
if X == 2 then
	--red dots
end

This is a Permutation with repetition and its fairly simple to calculate. the equation is n^r where n is the possible choices or outcomes and r is how many times n can be chosen. r in this case is 2 and n is 25 so 2^25 which is a shocking 33,554,432 possible outcomes. you can find out more about this at: Math Is Fun that explains this very well.