For in columns Range

[SamT]

this will work if there are no numbers below ActiveSheet.Range("[B to E]1").End(xlDown)

Dim rnbSuma As Range
Set rngSuma = Worksheets("hoja3").Range("F1")

For columna = 2 to 5 'Column B to Column E
rngSuma.Value = WorksheetFunction.Sum(Worksheets("hoja2").Columns(columna)) 
Set rngSuma = rngSuma.Offset(1)
Next columna

Set Seleccion = Range(ActiveSheet.Range("B1"), ActiveSheet.Range("B1").End(xlDown))
This is the same, but for any column number (columna)
Set Seleccion = Range(ActiveSheet.Cells(1, columna), ActiveSheet.Cells(1, columna).End(xlDown))



If you desire to move rngSuma to the right across columns, (F1 to G1 to H1 ...) then use .Offset(0 Rows, 1 columns)

Set rngSuma = rngSuma.Offset(0, 1)