I assume by "tab" you mean a worksheet, and I think you're saying you have
multiple worksheets, right? And I'm only guessing here, but since worksheets
don't have values themselves, by "last tab value" you might mean "the value
of some cell in the last worksheet". If so, you don't mean you want to
"substitute" the value in that cell, you just want to "display" it.

If all that is right, then I guess you want a cell in one worksheet to
display the sum of some cells in a range of other worksheets. And when you
say "according to selection", you mean... Ok, I give up on that one; I don't
know what you mean. Can you straighten me out?

--- "Seaq" wrote:
Hi, I am trying to figure out how to substitute the ending tab value by the
value in another cell

i.e. =SUM('04:03'!C46) , where tab name "03" need to change according to
selection.