The .Get... are class 'getters' and you can omit the Get part. It works both ways.
You do need to leave some room for both numbers, they may be large.
Place the code in B4XTable1_DataUpdated
B4XTable1.lblNumber.left = 40dip
B4XTable1.lblNumber.Width = 100dip
B4XTable1.lblNumber.TextSize = 18
B4XTable1.lblNumber.Text = B4XTable1.CurrentPage & "/" & Ceil((B4XTable1.Size / B4XTable1.RowsPerPage))