There are two methods.
1) You could highlight the row in question, and click on the
exclamation mark of the first numbered cell. Assuming you have Office
20003. A list of options will appear allowing you to convert numbers
stored as text to number.
2) The other is to write a loop statement
The following example will start at the selected cell on the
spreadsheet.
Dim lRange As Long
Dim l As Long
Dim iNum As Integer
lRange = Cells(Rows.Count, ActiveCell.Column).End(xlUp).Row
For l = 1 To lRange
iNum = Val(ActiveCell.Value)
ActiveCell.Value = iNum
ActiveCell.Offset(1, 0).Select
Next