Have I used math.random() right?

I am making a tower defence game and it was previously a 1 man server so I'm making it so multiple people can play in the same server but I need to give players there own numbers. Basically I want every player to have a different number, but ima make it so there is only 4 numbers. So I can address each player.

game.Players.PlayerAdded:connect(function(p)
	local stats = Instance.new("IntValue")
	stats.Name = "team2"
	stats.Parent = p
	
	local money = Instance.new("IntValue")
	money.Name = "which" 
	money.Value = 1 
	money.Parent = stats
	
	p.team2.which.Value = math.random(1,4)
end)

First of all, let's go over the correct use of math.random(). To get a basic random number, you would use this:

local randomNumber = math.random(1,10) --You did this correctly

You could generate random seeds for better random numbers. I will not explain those here, but you could look into them later.

From what I can understand, you are trying to seperate players into teams. However, let's go through your program by saying four people join. Let's say these are the following numbers that generated:

1,3,1,1

Team 3 would greatly outnumber Team 1. You would want to make an array of the possible teams to get on:

local teams = {1,2,3,4}

Now, we select a team from this table by using math.random():

local index = math.random(1,#teams) --Pick a position in the table
local team = teams[index] --Now we reference the team inside the table

Then set their team to the number:

p.team2.which.Value = team --I assume you want a number value

Then remove this from the table so it cannot be chosen again:

table.remove(teams,index) --This is why we got an index instead of just getting the team.

Hope this helped!