Review my simple VBA script with built-in Excel function - vba

Question

Suppose that I have Excel file consists of four worksheets, lets name them as 1, 2, 3 and 4. I want to evaluate a sum of all values from the cells AK10, AK25, AK40 and so on till AK160 on the worksheet 4 and then place it in the cell G23 of worksheet 2.
Here is my macro that I assign to worksheet 2:
Sub sum_up()
Dim i As Integer, s As Integer
s = 0
For i = 0 To 10
s = WorksheetFunction.Sum(s, Worksheets("4").Range("AK(10 + 15 * i)"))
Next i
Range("G23").Value = "s"
End Sub
It ends up with 400 error. What am I doing wrong?

Answer 1

Sub sum_up()
Dim i As Long, s As Long
s = 0
For i = 0 To 10
s = s + Worksheets("4").Cells(10 + 15 * i, "AK").Value
Next i
Range("G23").Value = s
End Sub

Answer 2

I'll take a crack at this - I'd really use a lot more named ranged to pass data back and forth...:
Sub sum_up()
Dim i As Integer, s As Integer
s = 0
For i = 0 To 10
s = s + Worksheets("4").Range("AK" & (10 + 15 * i))
Next I
Range("G23").Value = s
End Sub

Answer 3

you did not say that the summation was to be done using VBA
put this in G23 on worksheet2 (actually, put this in any cell)
=SUM('4'!AK10,'4'!AK25,'4'!AK40,'4'!AK55,'4'!AK70,'4'!AK85,'4'!AK100,'4'!AK115,'4'!AK130,'4'!AK145,'4'!AK160)
as far as what you are doing wrong with your code, that has partly been answered by #KenWhite
you are also putting the letter "s" into G23 of any worksheet that happens to be visible at the time your code runs
put in a reference to sheet 2, same as you referenced sheet 4 just two lines above
this code should work:
Sub sum_up()
Dim ws4 As Worksheet
Set ws4 = ActiveWorkbook.Sheets("4")
Dim rng As Range
Set rng = ws4.Range("ak10") ' point to "ak10"
Dim total As Long
total = rng.Value
Do While True
rng.Select
Set rng = rng.Offset(15) ' move pointer down 15 rows
If rng.Row > 160 Then Exit Do ' moved past row 160 ?
total = total + rng.Value
Loop
ActiveWorkbook.Sheets("2").Range("G23").Value = total
End Sub