I'm setting formulas in cells in VBA using R1C1

For example:

In Excel:
A1 = Sum(A2:A10) 'Assume RowStart = 2 RowEnd =10 ColNum =1

In VBA: 'Assume RowStart = 2 RowEnd =10 ColNum =1
Cells(1,1) = "=Sum(R" & RowStart & "C" & ColNum & ":R" & RowEnd & "C" &
ColNum & ")"

The resulting Excel formula in A1: =Sum($A$2:$A$10)

This works fine however I would like to omit the anchors should end users
need to change rows/columns around at a later date.

So that ending result would be A1=Sum(A2:A10)

Any suggestions?

Thanks!