Challenge 2: A Self-Expanding Table with a Structured Reference — Solution Walkthrough

1. Select A1:C50 (including headers: Product, Category, Price).
2. Press Ctrl+T, confirm "My table has headers," click OK.
3. In Table Design, rename the table from its default (e.g. "Table1")
   to SalesTable, using the Table Name box.

Formula (entered in any cell outside the table):
  =AVERAGE(SalesTable[Price])

What happens when 10 new rows are added directly below the table:

Typing data into the row immediately beneath the table's current
last row automatically extends the table to include that new row —
no re-selecting, no Ctrl+T again, nothing manual required. Because
the formula references SalesTable[Price] (the whole Price column of
the table) rather than a fixed address like C2:C50, it automatically
includes every one of the 10 new rows' prices in its average the
moment they're entered, with the formula itself completely
unchanged.

Explanation:

This is the core difference this chapter draws between a plain range
and a Table: =AVERAGE(C2:C50) would need to be manually rewritten to
=AVERAGE(C2:C60) to include the new rows, and it's easy to forget to
do that. =AVERAGE(SalesTable[Price]) instead means "the Price column
of SalesTable, whatever its current size happens to be" — the
reference isn't a snapshot of a specific set of cells, it's a live
description of the table's own column, so the formula's meaning
automatically grows along with the table itself.

Notes:
- The same automatic-inclusion behaviour applies to the table's
  filter dropdowns, its row banding, and its optional Total Row —
  all of it expands together, which is exactly why converting a
  range to a Table early is worth doing before a data set grows.