Small exercises that make data mistakes and decisions visible.
The Practice Lab uses compact files and clear questions. Learners produce something concrete that can be checked, revised and repeated.
Find the structural problem
A spreadsheet mixes headings, notes and data in the same area. Learners reorganize it into a consistent table and explain why the new structure makes filtering and checking easier.
Clean a small contact or inventory list
The file contains repeated records, empty fields and inconsistent category labels. Learners decide which values can be standardized automatically and which need human review.
Check a percentage before reporting it
A worked example contains a denominator error. Learners identify why the result is misleading, calculate the correct value and write a short explanation in plain language.
Choose the right chart for the question
Several chart options show the same small dataset. Learners compare which form best communicates a trend, category comparison or composition and explain the trade-offs.
Reduce a dashboard
An intentionally overloaded dashboard contains duplicated measures and decorative elements. Learners remove what does not answer the stated question and reorganize the remaining information.
Review is part of the exercise.
A finished spreadsheet is not automatically a good spreadsheet. The review stage asks whether the structure is understandable, the calculation can be checked and the chart or summary answers the intended question.
Worked examples show one reasonable approach and explain why it was chosen. When several solutions are valid, the material makes the trade-offs explicit.