商、剰余、べき乗 | ～ 車輪の再発明シリーズ ～ http://www.moug.net/faq/viewtopic.php?t=65743

Module1.bas

Option Explicit

Function Quotient(ByVal Dividend, ByVal Divisor) As Variant
    'Quotient = Dividend \ Divisor
    Quotient = Fix(Dividend / Divisor)
End Function

Function Modular(ByVal Dividend, ByVal Divisor) As Variant
    'Modular = Dividend Mod Divisor
    Modular = Dividend - Quotient(Dividend, Divisor) * Divisor
End Function

Module2.bas

Option Explicit

Function Power(ByVal Base As Long, ByVal Exponent As Long)
    If Exponent < 0 Then
        Err.Raise 5
    End If
    Power = Power_(CDec(Base), Exponent)
End Function
 
Private Function Power_(ByVal Base, ByVal Exponent As Long)
    'Power = Base ^ Exponent

    Static Memo As New Collection
    Dim Params As String
    Dim Visited As Boolean
    Dim Sum As Variant
    
    Params = Base & "^" & Exponent
    On Error Resume Next
    Power_ = Memo.Item(Params)
    Visited = Err.Number = 0
    On Error GoTo 0
    If Visited Then Exit Function
    
    If Exponent = 0 Then
        Sum = 1
    Else
        Sum = Base * Power_(Base, Exponent - 1)
    End If
    Power_ = Sum
    
    Memo.Add Sum, Params
End Function

Module3.bas

Option Explicit

Function Power(ByVal Base As Long, ByVal Exponent As Long)
    'Power = Base ^ Exponent

    Dim Sum As Variant
    Dim n As Long
    Dim i As Long
    
    If Exponent = 0 Then
        Sum = 1
    Else
        Sum = CDec(Base)
        n = Exponent - 1
        For i = 1 To n
            Sum = Sum * Base
        Next i
    End If
    
    Power = Sum
End Function