=ОКРУГЛ(B6;ВПР(ABS(B6);{0;4:1;3:10;2:100;1};2))

=ТЕКСТ(B6;"0,"&ПОВТОР(0;ВПР(ABS(B6);{0;4:1;3:10;2:100;1};2)))

Sub test()
     Dim i&, n&, r&, c&, v()
     v = ActiveCell.CurrentRegion.Value
     i = UBound(v, 2)
     For r = 1 To UBound(v)
         For c = 1 To i
             If Not IsEmpty(v(r, c)) And IsNumeric(v(r, c)) Then
                 Select Case Abs(v(r, c))
                     Case Is >= 100: n = 1
                     Case Is >= 10:  n = 2
                     Case Is >= 1:   n = 3
                     Case Else:      n = 4
                 End Select
                 v(r, c) = Round(v(r, c), n)
             End If
     Next c, r
     ActiveCell.CurrentRegion.Value = v
End Sub

Public Sub test()
Dim arrStr(1 To 4) As String
Dim i As Integer, j As Integer
arrStr(1) = "0,0000"
arrStr(2) = "0,000"
arrStr(3) = "0,00"
arrStr(4) = "0,0"

delI = ActiveCell.Row   
delJ = ActiveCell.Column   

rowNum = Selection.Rows.Count - 1
colNum = Selection.Columns.Count - 1

For i = delI To rowNum + delI
        For j = delJ To colNum + delJ
            If IsNumeric(Cells(i, j).Value) Then
            Select Case Cells(i, j).Value
                Case Is > 100
                    Cells(i, j).NumberFormatLocal = arrStr(4)
                Case Is > 10
                    Cells(i, j).NumberFormatLocal = arrStr(3)
                Case Is > 1
                    Cells(i, j).NumberFormatLocal = arrStr(2)
                Case Else
                    Cells(i, j).NumberFormatLocal = arrStr(1)
            End Select
            End If

        Next j
Next i

End Sub

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