Local addresses

The "A1" address system has coordinates that exist over the whole worksheet. If you have a block of data specified somewhere within that worksheet, it can be useful to be able to specify the addresses relative to that block.

This can be done with INDEX(), which takes 3 arguments. The first argument is a rectangular range of data, for example A2:E8. The second and third arguments are numbers specifying an offset down then right from the top left of that data range. Unlike OFFSET(), the numbering starts at 1, so INDEX(A2:E8, 4, 2) refers to cell B5.