calculation in VB

ws.Cells(iRow, 24).Value = Me.basic.Value
ws.Cells(iRow, 25).Value = Me.hra.Value
ws.Cells(iRow, 26).Value = Me.conv.Value
ws.Cells(iRow, 27).Value = Me.others.Value
ws.Cells(iRow, 28).Value = Me.mf.Value
ws.Cells(iRow, 29).Value = Me.pf.Value
ws.Cells(iRow, 30).Value = Me.esic.Value

ws.Cells(iRow, 31).Value = Me.gross.Value

how can i calculate this gross automatically