Formulas

The dozen Excel formulas that cover 90% of real work — SUM, IF, SUMIF, VLOOKUP and XLOOKUP, text and date functions, plus absolute references and IFERROR.

Use VLOOKUP effectively in Excel — the four arguments, why you always end with FALSE, locking the table, cross-sheet lookups, IFERROR, and when to switch to XLOOKUP.

The Excel mouse habits quietly costing you time — and the single keystroke that kills each. Stop scrolling, dragging, copy-pasting, and ribbon-hunting.

Excel data validation that keeps entries clean — dropdown lists, number and date rules, input messages, custom-formula checks, dependent dropdowns, and Circle Invalid Data.

Build Excel charts that earn their place in a report — match the chart to your message, strip the clutter, use combo charts and sparklines, and wire visuals to live data.

The Google Sheets QUERY function, clause by clause — SELECT, WHERE, GROUP BY, ORDER BY and LIMIT — to filter, summarize, and rank a dataset in one live formula.

ARRAYFORMULA runs one formula down a whole column: stretch IF and VLOOKUP across rows, auto-number, and skip it when FILTER or QUERY already spills.

Use IMPORTRANGE to pull live data between Google Sheets: the syntax, the one-time permission, update limits, and QUERY/FILTER for real reports.