I want to extract the row or column values from a cell that is referencing
another cell so that I can use it in a third.

For cell 1 the formula is =Sheet1$AE$75, I want to be able to extract 75 so
I can use it in another cell such as Sum($BB$1:$BB$nn) where nn would be the
value 75. I have a lot of referenced columns that I need to sum. Their range
would be the same for a summary attempt but that range may need to change. So
I don't want to do a "replace all" function every time I need to use a
different number of rows.

I thought there was a substring extract function but I can't seem to find it.