Non-working VBA math game

Option Explicit
Private mathQuestions() As Integer
Private mathOperators() As String
Private userAnswers() As Integer
Private opType As Integer
Private numQuestions As Integer
Private curDate As Date
Private gameRunning As Boolean
Private Sub optAdd_Click()
    Range("Operator").Value = "+"
    opType = 1
End Sub
Private Sub optSubtract_Click()
    Range("Opertator").Value = "-"
    opType = 2
End Sub
Private Sub optMultiply_Click()
    Range("Operator").Value = "x"
    opType = 3
End Sub
Private Sub optDivide_Click()
    Range("Operator").Value = "/"
    opType = 4
End Sub
Private Sub optAny_Click()
    Range("Operator").Value = ""
End Sub
Private Sub cmdBegin_Click()

    EnableControls False
    numQuestions = 0
    gameRunning = True
    Range("A2:C" & UsedRange.Rows.Count).ClearContents
    Range("Answer").Select
    Application.MoveAfterReturn = False

    GetOperatorType
    GetOperands

    curDate = Now
    MathGame
End Sub
Private Sub EnableControls(ctrlsEnabled As Boolean)
    cmdBegin.Enabled = ctrlsEnabled
    optAdd.Enabled = ctrlsEnabled
    optSubtract.Enabled = ctrlsEnabled
    optMultiply.Enabled = ctrlsEnabled
    optDivide.Enabled = ctrlsEnabled
    optAny.Enabled = ctrlsEnabled
End Sub
Private Sub GetOperatorType()
    If optAdd.Value = True Then opType = 1
    If optSubtract.Value = True Then opType = 2
    If optMultiply.Value = True Then opType = 3
    If optDivide.Value = True Then opType = 4
    If optAny.Value = True Then GetRandomOperator
End Sub
Private Sub GetRandomOperator()
    Randomize
    opType = Int(4 * Rnd) + 1
    Select Case opType
        Case Is = 1
            Range("Operator").Value = "+"
        Case Is = 2
            Range("Operator").Value = "-"
        Case Is = 3
            Range("Operator").Value = "x"
        Case Is = 4
            Range("Operator").Value = "/"
        Case Else
            Range("Operator").Value = "+"
    End Select
End Sub
Private Sub GetOperands()
    Dim rightOperand As Integer

    rightOperand = GetRandomNumber(1)
    Range("RightOperand").Value = rightOperand
    Range("LeftOperand").Value = GetRandomNumber(rightOperand)
End Sub
Private Function GetRandomNumber(divisibleBy As Integer) As Integer
    Dim ranNum As Integer
    Const upperLimit = 10

    Randomize

    Do
        ranNum = Int(upperLimit * Rnd) + 1
    Loop Until ((opType <> 4) Or (ranNum Mod divisibleBy = 0))

    GetRandomNumber = ranNum
End Function
Private Sub MathGame()

    Dim numSeconds As Integer
    Dim nextTime As Date
    Const TIMEALLOWED = 60

    numSeconds = 1

    nextTime = Now + TimeValue("00:00:10")
    Application.OnTime EarliestTime:=nextTime, _
    Procedure:="MathGameSheet.MathGame", Schedule:=True

    Do
    If (nextTime) Then
        Range("Clock").Value = Range("Clock").Value - numSeconds
    Else
        Range("Clock").Value = TIMEALLOWED
    End If
    Loop Until Range("Clock").Value = 0

    If (Range("Clock").Value = 0) Then
        gameRunning = False
        Range("Clock").Value = TIMEALLOWED
        Application.OnTime EarliestTime:=nextTime, _
        Procedure:="MathGameSheet.MathGame", Schedule:=True
        EnableControls True
        ClearBoard
        ScoreAnswers
        Application.MoveAfterReturn = True
    End If
End Sub
Private Sub Worksheet_Change(ByVal Target As Range)

    If (Target.Address = "$L$8") And _
    (Range("Answer").Value <> "") And gameRunning Then
        numQuestions = numQuestions + 1
        StoreQuestions
        If optAny.Value = True Then
            GetRandomOperator
        End If
        GetOperands
        Range("Answer").Select
        Selection.Value = ""
    End If
End Sub
Private Sub StoreQuestions()
    ReDim Preserve mathQuestions(1, numQuestions) As Integer
    ReDim Preserve mathOperators(numQuestions) As String
    ReDim Preserve userAnswers(numQuestions) As Integer

    mathQuestions(0, numQuestions - 1) = Range("LeftOperand").Value
    mathQuestions(1, numQuestions - 1) = Range("RightOperand").Value
    mathOperators(numQuestions - 1) = Range("Operator").Value
    userAnswers(numQuestions - 1) = Val(Range("Answer").Value)
End Sub
Private Sub ClearBoard()
    Range("LeftOperand").Value = ""
    Range("RightOperand").Value = ""
    Range("Answer").Value = ""
End Sub
Private Sub ScoreAnswers()
    Dim I As Integer
    Dim numWrong As Integer

    For I = 0 To numQuestions - 1
        Cells(I + 2, "A").Value = mathQuestions(0, I) & _
        mathOperators(I) & mathQuestions(1, I)
        Cells(I + 2, "B").Value = userAnswers(I)
        If mathOperators(I) = "x" Then
            Cells(I + 2, "C").Formula = "=" & _
            mathQuestions(0, I) & "*" & mathQuestions(1, I)
            Cells(I + 2, "B").Font.Color = RGB(0, 0, 0)
        Else
            Cells(I + 2, "C").Formula = "=" & _
            mathQuestions(0, I) & mathOperators(I) & mathQuestions(1, I)
            Cells(I + 2, "B").Font.Color = RGB(0, 0, 0)
        End If

        If Cells(I + 2, "B").Value <> Cells(I + 2, "C").Value Then
            Cells(I + 2, "B").Font.Color = RGB(255, 0, 0)
            numWrong = numWrong + 1
        End If
    Next I

    Cells(I + 2, "A").Value = "Score (%)"
    Cells(I + 2, "B").Font.Color = RGB(0, 0, 0)
    Cells(I + 2, "B").Formula = "=" & _
    (numQuestions - numWrong) / numQuestions & "*100"
End Sub