IFERROR is a seatbelt, not a blindfold — wrap the truly missing, fix the merely broken.
The board pack reads its segment numbers off the tape, and three of the five reads came back #N/A this morning — for three different reasons. One queries a segment that was divested and is genuinely gone from the tape: that error is TRUE, and the pack wants a zero. The other two are merely broken. Get all five reading, foot the panel, and close it. A fallback is for the truly missing; a repair is for the merely broken.
Alt walks: tap Alt, release, then the letters in sequence — each key steps one ribbon menu. On a Mac, tap ⌥ and use the same letters (KeyTips, Excel 2024+).
F2⌃U · fn F2 on macEdit the active cell (cursor at the end)
Edit-in-place lights up every cell a formula touches — the first move when a number looks wrong.
Shift+↓⇧↓ on macExtend selection one cell
Ctrl+D⌘D on macFill down from the cell above
Build the logic once in the top cell, select down, and stamp it — the standard way to fill a schedule.
Alt+=⌥ = on macAutoSum the adjacent range
AutoSum reads the block above or beside the cursor and proposes the SUM — foot rows and columns without typing a formula.
Shift+→⇧→ on macExtend selection one cell
Nudge a selection one cell at a time when the block you need doesn’t end at a data edge.
Ctrl+B⌘B on macBold
Bold marks structure: titles, total rows, anything the reviewer’s eye should land on first.
Alt h b p⌥ h b p on macTop border
Top border above a total row — the accounting ruling that says “this line sums the ones above.”
functions you'll type: IFERROR()
the par-setting sequence, straight through:
wrap B18 → =IFERROR(the read,0) · repair B16:B17 from the healthy read above them — select B15:B17 ctrl+d · B20 alt+= ↵ · A20:B20 ctrl+b · alt h b p · ctrl+s