Challenge 1: Predicting a Clean Round-Trip — Solution Walkthrough

Prediction: opening and re-saving this workbook in Calc is very
unlikely to cause any visible changes.

Reasoning:

The workbook's actual contents — plain formulas, standard formatting,
and a basic column chart — sit squarely within this chapter's own
"usually survives cleanly" category. None of the specific risk areas
this chapter identifies for spreadsheets are present here: there's no
mention of a genuinely new or unusual function (the main formula-
level risk from Chapter 5), no complex conditional formatting rules,
and a "basic column chart" is exactly the kind of standard chart type
this chapter describes as translating reliably, rather than one of
the less-common chart subtypes flagged as a shift risk. With none of
the genuine risk factors present, there's no real reason to expect
anything beyond a clean, unremarkable round-trip.

WHY THIS WORKS AS AN ANSWER
------------------------------
This exercise tests whether the chapter's own "most things survive
cleanly, only specific advanced features are actually at risk"
framing was understood correctly — the right instinct isn't blanket
anxiety about every file conversion, it's recognising which SPECIFIC
features (from this chapter's own lists) a given file actually
contains before predicting any risk at all.