Trim All Cells In A Sheet

I'm trying to trim all the data in my worksheet in order to prepare it for several steps of further analysis. Running the below code will cause an error that I don't understand. It says:

Runtime error '1004': Application-defined or object-defined error

the code is (error causing line indicated in comments):

PHP

Sub trimAll()
    Application.ScreenUpdating = False
    Dim Rows As Long
    Dim Column As Long
    Dim i As Integer
        Rows = ActiveSheet.UsedRange.Rows.Count
        Column = ActiveSheet.UsedRange.Columns.Count
    For i = 1 To Column
            Columns(i).Select
            Selection.Insert Shift:=xlToRight
            ActiveSheet.Range(Cells(1, i), Cells(Number, i)) = "=TRIM(RC[1])"  ** ERROR **
            Columns(i).Select
            Selection.Copy
            Columns(i + 1).Select
            Selection.PasteSpecial Paste:=xlValues, Operation:=xlNone, SkipBlanks:= _
                False, Transpose:=False
            Columns(i).Select
            Selection.Delete Shift:=xlToLeft
    Next i
    Application.ScreenUpdating = True
End Sub