Data Store script gives and arithmetic error? And I have no clue why XD?

I was recently messing around with data store and a couple tutorials later I ended up with this, which I like very much except for the fact that it errors on.

It errors on the line that says if i % 2 == 0 then... So on and so on

It says it errors because its arithmetic (a string value)

Heres the code

local DS = game:GetService("DataStoreService"):GetDataStore("39001837")
local DataFile = game:GetService("ServerStorage"):WaitForChild("DataFile")

local autoSaveInterval = 60

game.Players.PlayerAdded:connect(function(player)
    local playerFolder = Instance.new("Folder", DataFile)
    playerFolder.Name = player.Name

    local Units = Instance.new("IntValue", playerFolder)
    Units.Name = "Units"

    local Crystals = Instance.new("IntValue", playerFolder)
    Crystals.Name = "Crystals"

    local GetAsync = DS:GetAsync(player.UserId)

    if GetAsync then
        print("Space used ".. game:GetService("HttpService"):JSONEncode(GetAsync):len().."/260000")
        for i,v in pairs(GetAsync) do
            print(i,v)
            if i % 2 == 0 then
                DataFile[player.name].playerFolder:FindFirstChild(GetAsync[i - 1]).Value = v
            end
        end
    end
end)

local function saveData(player)
    local savedData = {}
    for i,v in pairs(DataFile[player.Name].playerFolder:GetChildren()) do
        savedData[#savedData + 1] = v.Name
        savedData[#savedData + 1] = v.Value
    end
    DS:SetAsync(player.UserId, savedData)
end

game:BindToClose(function()
    for i, player in pairs(game.Players:GetPlayers()) do
        saveData(player)
    end
end)

game.Players.PlayerRemoving:connect(function(player)
    saveData(player)
end)

Does anyone have any ideas im pretty sure its a simple fix. :)

Thank you for your time.