Error 1004 when multiplying cell values based on criteria - vba

Question

I have a macro which looks at a range of cells. Every other cell is either a 1 or a 0 (sign bit). Depending on the sign bit, the next cell (a normal number) is multiplied either by 1 or 0. I keep getting a run time error 1004 Application-defined or object-defined error on the body of the ElseIf of the If statement (indicated below). Not sure what I'm doing wrong. My code is in a "proof-of-concept" stage so it's still pretty hackish.
Dim N As Long
------------------------------------------
Private Sub CommandButton1_Click()
Dim x As Integer
Dim y As Integer
x = 0
y = 1
N = Application.InputBox(Prompt:="Enter value", Type:=1)
If N > Columns.Count Then
N = Columns.Count
Else
For i = 4 To 9999
Cells(1, i).ClearContents
Cells(3, i).ClearContents
Next i
End If
For i = 4 To N + 3
x = x + y
Cells(1, i) = x
Next i
For i = 4 To N + 3
If Cells(2, i) = 1 Then
Cells(2, i).Offset(0, 1).Select = Cells(2, i).Offset(0, 1).Select * -1
ElseIf Cells(2, i) = 0 Then
'This is the line with errors vvvvvvvvvvvvvvvvv
Cells(2, i).Offset(0, 1).Select = Cells(2, i).Offset(0, 1).Select * 1
End If
Next i
End Sub

Answer 1

That's because you're using Select. Obviously, Select and Activate don't give you values. They select or activate the cell, not different from manually clicking on them using the mouse or moving/activating to them using the keyboard or what else. Multiplying them by a value is a major no-no.
The Range property you should be looking for is Value. In any case, I think you're making it difficult because of having two loops. You really should reconsider your design pattern. In any case, here's my approach (mine's vertical, but it seems like yours is horizontal, so be clear exactly what is on your end so this can be adjusted).
Private Sub CommandButton1_Click()
Dim WS As Worksheet
Dim LastRow As Long
Dim Iter As Long
Dim CurrCell As Range
Const Col = 1
With ThisWorkbook
Set WS = .Sheets("Sheet3") 'Change as necessary.
End With
With WS
LastRow = .Range("A" & .Rows.Count).End(xlUp).Row
For Iter = 1 To LastRow 'Change as necessary.
Set CurrCell = .Cells(Iter, Col)
Select Case CurrCell.Value
Case 1
CurrCell.Offset(0, 1).Value = (CurrCell.Offset(0, 1).Value * (-1))
Case 0
CurrCell.Offset(0, 1).Value = (CurrCell.Offset(0, 1).Value * 1) 'Is this even necessary? It's an identity.
End Select
Next
End With
End Sub
Screenshot:
Let us know if this helps.