Resilient Excel Spreadsheets
Upgrade from fragile, manual spreadsheets to modern, dynamic workbooks. Learn to replace nested IFs, retire brittle lookups with XLOOKUP, and build self-updating models using dynamic arrays and structured tables.
Like Duolingo, but for Resilient Excel Spreadsheets. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
A short one: 10 levels across 2 sections, about 20 minutes end to end, roughly 4 days at five minutes a day. It moves through Formulas That Don't Break and Dynamic and Self-Updating Layouts. It assumes you already know the basics.
Free forever · No credit card · iPhone & Android
Key ideas in Resilient Excel Spreadsheets
- VLOOKUP relies on a hardcoded column index number that does not shift when columns are inserted.
- XLOOKUP uses a direct cell range reference for its return vector that adjusts automatically when columns move.
- XLOOKUP decouples lookup and return ranges so the return column can sit anywhere, even to the left.
- XLOOKUP includes a dedicated fourth argument specifically for missing value fallback text.
- Using the built-in not-found argument avoids masking unexpected calculation errors that IFERROR hides.
- XLOOKUP defaults to an exact match of 0, so unsorted data tables will not produce silent wrong answers.
- VLOOKUP defaults to approximate matching, which returns false near-matches if the table is unsorted.
- XLOOKUP only performs approximate or wildcard searches when explicitly told via the match_mode parameter.
- The inner XLOOKUP evaluates a horizontal header row and returns an entire vertical column vector.
- The outer XLOOKUP searches vertically within that returned dynamic column vector for the target row item.
- Nesting lookup vectors replaces the static coordinates of traditional INDEX-MATCH two-way grids.
- IFS tests condition-result pairs in a single list without closing parenthesis stacks
- IFS stops and returns the value for the first true condition encountered
- A final TRUE argument serves as an explicit fallback catch-all in IFS
- SWITCH evaluates a single expression once against multiple exact values
- SWITCH eliminates repeating cell references in equality checks
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives Resilient Excel Spreadsheets the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
You insert a new column into your data table. Why does XLOOKUP continue returning the correct values?
Get it right to open this lesson and 9 more in the app.
Where Resilient Excel Spreadsheets takes you
- 1
Formulas That Don't Break
- Modern Lookups with XLOOKUP
- Clean Multi-Condition Logic
- 2
Dynamic and Self-Updating Layouts
- Dynamic Arrays and Spill Ranges
- Structured Tables as Reliable Foundations
2 sections · 4 units · 10 levels. Built to play, not to enroll.
You pick the voice
Resilient Excel Spreadsheets is taught in the The Professor style: clear, structured, thorough. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
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Start Resilient Excel Spreadsheets today.
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