配列hairetuに"11","22","33","44","55"と5つの要素が入っています。
Private Sub CommandButton1_Click()
Dim hairetu As Variant
Dim i As Long
Dim n As Long
hairetu = Array("11", "22", "33", "44", "55")
For i = 0 To UBound(hairetu)
n = n + hairetu(i)
Next i
n = n / (UBound(hairetu) + 1)
MsgBox n
End Sub