Modifica numero foglio di lavoro quando supero 100

 Sub numera() 
Dim prev() 
Dim sh As Worksheet 
ReDim Preserve prev(Worksheets.Count) 
Max = 0 
For i = 1 To Worksheets.Count     
           prev(i) = Split(Worksheets(i).Name, "21-10") 'fino a 100 usare ->21-0 dopo 21-10     
           On Error Resume Next     
           If prev(i)(1) > Max Then Max = prev(i)(1)     
           On Error GoTo 0 
Next i 
Max = Max + 1 Worksheets("master (2)").Name = "21-10" & Max 'fino a 100 usare ->21-0 dopo 21-10 
Call EstraiNomeFoglio 
End Sub

 ...............   
           prev(i) = Split(Worksheets(i).Name, "21-0")     
           ............
           Max = Max + 1 Worksheets("master (2)").Name = "21-0" & Max 
           .............

 ...............   
           prev(i) = Split(Worksheets(i).Name, "21-10")     
           ............
           Max = Max + 1 Worksheets("master (2)").Name = "21-10" & Max 
           .............

Sub numera2()
Dim N As Long, A As String
A = "21-" ' Anno ed -
N = Worksheets.Count + 1
    Sheets("master").Copy After:=Sheets(Sheets.Count)
    If N < 10 Then
        ActiveSheet.Name = A & Format(N, "0")
    ElseIf N < 100 Then
        ActiveSheet.Name = A & Format(N, "00")
    ElseIf N < 1000 Then
        ActiveSheet.Name = A & Format(N, "000")
    End If
End Sub

    If N < 100 Then
        ActiveSheet.Name = A & Format(N, "00")
    ElseIf N < 1000 Then
        ActiveSheet.Name = A & Format(N, "000")
    End If

-----------
prev(i) = Split(Worksheets(i).Name, "21-") 'by Marius     
--------
Worksheets("master (2)").Name = prev(0) & "21-" & Max 'by Marius

Sub numera()
Dim i As Long
Dim mx As Integer
Dim nomefoglio As String
Dim prev
Dim sh As Worksheet
mx = 0
For i = 1 To Worksheets.Count
    On Error Resume Next
    If Left(Worksheets(i).Name, 3) = "21-" Then
      prev = Split(Worksheets(i).Name, "-") 'by Marius
    End If
    On Error GoTo 0
Next i
mx = Val(prev(1)) + 1
'QUI ASSEGNI IL NOME DEL NUOVO FOGLIO DOPO AVER CREATO LE TRE CIFRE
nomefoglio = prev(0) & "-" & Right("000" & mx, 3)
Stop
Call EstraiNomeFoglio
End Sub

Sub InsFoglio()
Dim CurYear As String, mMaster As Worksheet, j As Integer, arrNumb(), mSheet As String
Set mMaster = Worksheets("master")
CurYear = "21" ' <<< eventualmente prendi valore da cella di Master (?)
k = 0
' cerco eventuale ultimo foglio
For j = 1 To Sheets.Count
    If Left(Sheets(j).Name, 2) = CurYear Then
        ReDim Preserve arrNumb(k)
        mpos = 4
        arrNumb(k) = Mid(Sheets(j).Name, mpos, Len(Sheets(j).Name)) * 1
        k = k + 1
    End If
Next j
' se già non esiste creo 001, altrimenti incremento
If k > 0 Then
    mMax = WorksheetFunction.Max(arrNumb) + 1
Else
    mMax = 1
End If
mSheet = CurYear & "-" & Format(mMax, "000")
mMaster.Copy after:=Sheets(Sheets.Count)
ActiveSheet.Name = mSheet
'cancello pulsante comando nel foglio creato
ActiveSheet.Shapes("NewS").Delete
End Sub

 CurYear = Format(mMaster.Range("AC35"), "yy") 

Option Explicit

Sub InsFoglio()
Dim CurYear As String, mMaster As Worksheet, j As Integer, arrNumb(), mSheet As String
Dim mBefore As String, k As Integer, mPos As Byte, mMax As Integer
On Error GoTo errori
Application.Calculation = xlCalculationManual
Set mMaster = Worksheets("master")
CurYear = Format(mMaster.Range("AC35"), "yy")
k = 0
' cerco eventuale ultimo foglio
For j = 1 To Sheets.Count
    If Left(Sheets(j).Name, 2) = CurYear Then
        ReDim Preserve arrNumb(k)
        mPos = 4
        arrNumb(k) = Mid(Sheets(j).Name, mPos, Len(Sheets(j).Name)) * 1
        k = k + 1
    End If
Next j
' creo nome progressivo destinazione e variabile foglio prima del quale va inserito
If k > 0 Then
    mMax = WorksheetFunction.Max(arrNumb) + 1
    mBefore = CurYear & "-" & Format(mMax - 1, "000")
Else
    mMax = 1
    mBefore = "Config"
End If
mSheet = CurYear & "-" & Format(mMax, "000")
mMaster.Copy before:=Sheets(mBefore)
ActiveSheet.Name = mSheet
'cancello pulsante comando nel foglio creato
ActiveSheet.Shapes("NewS").Delete
Application.Calculation = xlCalculationAutomatic
esci:
Exit Sub

errori:
MsgBox Err.Number & " - " & Err.Description
Resume esci
End Sub

......
.....
ActiveSheet.Shapes("NewS").Delete

esci:
Application.Calculation = xlCalculationAutomatic
Exit Sub
errori:
MsgBox Err.Number & " - " & Err.Description
Resume esci
End Sub