"make a roblox script for a leader stat called Robux when a player gets kill kill it goes up by 1 when a player dies it goes down by 1"

-- server script 
local Players = game:GetService("Players")

function onCharacterAdded(character)
	local leaderstats = Instance.new("Folder", character)
	leaderstats.Name = "leaderstats"
	
	local Robux = Instance.new("IntValue", leaderstats)
	Robux.Name = "Robux"
	
	character.Humanoid.Died:Connect(function()
		Robux.Value = Robux.Value - 1
	end)
end

function onPlayerAdded(player)
	player.CharacterAdded:Connect(onCharacterAdded)
	player.CharacterRemoving:Connect(function()
		player.CharacterAdded:Wait():Connect(onCharacterAdded)
	end)
end

function onPlayerRemoving(player)
	local character = player.Character
	if character then
		local leaderstats = character:FindFirstChild("leaderstats")
		if leaderstats then
			local Robux = leaderstats:FindFirstChild("Robux")
			if Robux then
				Robux.Value = Robux.Value - 1
			end
		end
	end
end

Players.PlayerAdded:Connect(onPlayerAdded)
Players.PlayerRemoving:Connect(onPlayerRemoving)

function onPlayerKill(killer, killed)
	local leaderstats = killer.Character:FindFirstChild("leaderstats")
	if leaderstats then
		local Robux = leaderstats:FindFirstChild("Robux")
		if Robux then
			Robux.Value = Robux.Value + 1
		end
	end
end

game.Workspace.Events.PlayerKill.OnServerEvent:Connect(onPlayerKill)

-- Make sure to create a RemoteEvent called "PlayerKill" in Workspace.Events
-- Call this event from your kill script like this:
-- game.Workspace.Events.PlayerKill:FireServer(killer, killed)