VB编程求平均值显示溢出

Private Sub Command1_Click()
msg$ = "请输入分数(-1结束)"
msgtitle$ = "输入数据"
start:
score = InputBox(msg$, msgtitle$)
score = Val(score)
If score < 0 Or score > 100 Then
 GoTo finish
Else
 total = total + score
 n = n + 1
  If score < 60 Then
   n1 = n1 + 1
  Else
   n2 = n2 + 1
   End If
 End If
 GoTo start
finish:
 End Sub
Private Sub Command2_Click()
 Text1.Text = Str$(n2)
 Text2.Text = Str$(n1)
 Text3.Text = Str$(total / n)
End Sub

Private Sub Command3_Click()
n = 0: n1 0: n2 = 0: total = 0
End
End Sub

Private Sub Form_Load()
Dim n As Single
Dim n1 As Single
Dim n2 As Single
Dim score As Single
Dim totol As Single
End Sub