Can someone help me with this random.math script because its only working for one of the valiues?

Hello,

I am trying to make a math.random() values but its only taking 1 and not 2 why?

script.Parent.Bet.Conrim.MouseButton1Click:Connect(function()
    script.Parent.mainFrame.Reward.MoneyToGet.Value = script.Parent.Bet.Bet.Text
    script.Parent.Bet.Visible = true
    local WinningColor = math.random(1,3)
    if WinningColor == 1 then
        for i = 1,3 do
            script.Parent.mainFrame.Green.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Black.BackgroundTransparency = 0.6
            wait(.3)
            script.Parent.mainFrame.Red.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Black.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Green.BackgroundTransparency = 0
            wait(.3)
            script.Parent.mainFrame.Green.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Red.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Black.BackgroundTransparency = 0
            wait(.3)
            script.Parent.mainFrame.Green.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Black.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Red.BackgroundTransparency = 0
            wait(.3)
        end
        if WinningColor == 2 then
            for i = 1,3 do
            script.Parent.mainFrame.Green.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Black.BackgroundTransparency = 0.6
            wait(.3)
            script.Parent.mainFrame.Red.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Black.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Green.BackgroundTransparency = 0
            wait(.3)
            script.Parent.mainFrame.Green.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Red.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Black.BackgroundTransparency = 0
            wait(.3)
            script.Parent.mainFrame.Green.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Black.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Red.BackgroundTransparency = 0
            wait(.3)
            script.Parent.mainFrame.Black.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Red.BackgroundTransparency = 0.6
            script.Parent.mainFrame.Green.BackgroundTransparency = 0
            wait(.3)
            end
        end
    end
end)