I am trying to figure out a macro or a formula that will allow me to keep a
running total when one cell in the formula is constantly changing.

Example:

Cell B6 contains the number 7 (total for this week)
Cell B35 contains the number 36 (year to date total including the 7 for this
week)

I want to be able to change cell B6 and have the new amount added to the 36
in cell B35 and the answer to that total, replace the year to date total in
Cell B35.

So, if cell B6 changes to 9 (total for the week) then I want the B35 total
to change to the 36 year to date pluse the 9 for the new weekly total and
ultimately replace the B35 cell number of 36 with the answer which is 45.

Does anyone know how I can do this?