Challenge 1: Navigating with the Name Box — Solution Walkthrough

1. Open a new blank workbook (Ctrl+N, or "Blank workbook" from the
   Excel start screen).
2. Click into the Name Box — the small input field directly above
   column A, to the left of the formula bar (it normally shows the
   address of whichever cell is currently selected, e.g. "A1").
3. Type Z100 and press Enter. The view jumps directly to cell Z100,
   with no scrolling required.
4. Click the Name Box again, type AB4, and press Enter. The view
   jumps to cell AB4.

Explanation:

Z100 means "column Z, row 100" — the 26th column, 100 rows down.
AB4 means "column AB, row 4" — column AB is the 28th column overall,
NOT the 2nd. Once single letters run out at Z (the 26th letter),
Excel continues with two-letter columns: AA (27th), AB (28th), AC
(29th), and so on, the same way a car odometer rolls over from 9 to
10 rather than starting a completely new counting system.

AB comes after Z (not after A) because column letters work like a
base-26 counting system read left to right, the same logic as how
"10" comes after "9" in ordinary counting rather than restarting at
"0-0". The first letter marks how many complete "rounds" of A-Z have
been used up, and the second letter picks the position within the
current round.

Notes:
- This is exactly why the Name Box is worth learning early — jumping
  to Z100 by pressing the arrow key or scrolling 100 times down and
  26 columns across would be slow and error-prone by comparison.
- The Name Box accepts any valid cell address, including ranges
  (e.g. typing A1:C10 and pressing Enter selects that whole range).