Why doesnt this script print a random value?

I have recently been making where I need trash to appear in a specific area, however my script doesnt work. The output says that there is a error in line 13.

local TrashSpawnHere = game.Workspace.TrashSpawnHere

local function CreateTrash()
    local Trash = game.Workspace.TrashPart
    local TrashClone = Trash:Clone()
    TrashClone.Parent = game.Workspace

    local TrashSpawnHereSizeX = TrashSpawnHere.Size.X
    local XPostion = TrashSpawnHere.CFrame.X
    print(XPostion)
    local SecondValueX = XPostion - TrashSpawnHereSizeX
    print(SecondValueX)
    local XPositionRandom = math.random(XPostion,SecondValueX)

    local TrashSpawnHereSizeZ = TrashSpawnHere.Size.Z
    local ZPosition = TrashSpawnHere.CFrame.Z
    print(ZPosition)
    local SecondValueZ = ZPosition - TrashSpawnHere
    print(SecondValueZ)
    local ZPositionRandom = math.random(ZPosition,SecondValueZ)
end

while true do 
    CreateTrash()
    wait(2)
end