Tables and comparisons

This lesson is still being tested: it improves with learners' feedback. If something is unclear, it is the lesson that needs fixing, not you.

By the end of this lesson, you will be able to

get a table with the columns you choose;
make numbers comparable (same unit, same period);
spot a made-up cell and replace it with “not specified”;
bring the table into your spreadsheet, and check the calculations.

Why it matters to you

Choosing a plan, a supplier, a device or a home means comparing. A clear table makes the decision obvious. But a table looks serious: a made-up cell or a wrong calculation is harder to see in it than in a text. This lesson teaches you to get a correct comparison, and to check it in five minutes.

Before you start


You need	Your assistant, free account, and a calculator; your spreadsheet if you have one
Cost	€0
Duration	35 minutes
Reminder	The offers in the example are invented; for your real options, take the prices from the official pages, with their date

Understand it in 3 minutes

A good table request says:

What you specify	Example
The rows: the options being compared	The 3 gyms
The columns: the criteria that matter to you	Cost over one year, commitment, opening days, what is included
The common unit	All costs over one year, with the working shown
The gap rule	“If information is missing, write ‘not specified’”

Facts first, opinion after. The table presents the facts. The recommendation comes afterward, separately, with your criteria (“I want to go on Sundays”). Otherwise, the AI mixes its preferences with the facts.

Calculations get checked. A generative AI predicts text: when it calculates “in its head”, it can get it wrong. Some tools (data analysis, code execution) calculate with code, but still redo by hand the calculations that decide your choice. Ask for the working of each calculation.

Do it together

The three offers are invented.

1Step 1: The table, with its rules

Make a comparison table of these 3 gym offers.
Columns: cost over one year (with the working shown), commitment, opening days, what is included.
Use only my notes: if information is missing, write "not specified". Don't give your opinion yet.

Gym A: €29 per month, 12-month commitment, €49 sign-up fee, open every day (7 j/7)
Gym B: €299 per year, paid in one payment, no sign-up fee, closed on Sundays
Gym C: €7 per week, no commitment, no sign-up fee, group classes included

2Step 2: Redo the calculations

With your calculator:

Gym A: 29 × 12 + 49 = €397 over one year;
Gym B: €299 over one year;
Gym C: 7 × 52 weeks = €364 over one year (we compare over 52 weeks; for a real offer, look at how it is billed over the year).

If a number in the table is different, say so: “The cost of gym C is wrong: 7 × 52 = €364. Fix it.”

3Step 3: Hunt for made-up cells

Compare each cell with the notes. The opening days of gym C are not given, nor what is included in gyms A and B, nor the commitment of gym B (“paid in one payment” doesn’t say how long you are committed): these cells must say “not specified”. If the table shows anything else, it is an invention.

Watch out for deductions too: “closed on Sundays” doesn’t mean gym B is open every other day.

4Step 4: The opinion, separate, with your criteria

Now, your opinion: I want to be able to go on Sundays, and I'm not sure I'll last a year. Which one do you recommend, and why? Also tell me what I should check before signing up.

A good answer rules out gym B (closed on Sundays), compares A and C (A commits you for 12 months, C has no commitment), and asks you to check whether gym C is open on Sundays, since your notes don’t say.

5Step 5: Bring the table over

Copy the table and paste it into your spreadsheet. If everything lands in a single column, ask:

Give me this table in CSV format, with a comma between the columns.

Copy the result into a plain text editor. On Mac, in TextEdit, first choose Format > Make Plain Text, because TextEdit creates RTF documents by default.
Save the file, then change its extension to .csv (TextEdit saves as .txt: check that the name doesn’t end in .csv.txt; on Windows, in Notepad, type the name with .csv directly, and if File Explorer doesn’t show extensions, turn them on with View > Show > File name extensions).
Open it with your spreadsheet, or use its import function. If accents or the € sign look garbled in Excel (for example “Ã©” instead of “é”), don’t open the file with a double-click: on the Data tab, click From Text/CSV, choose the file, then pick UTF-8 as the encoding.

Your turn

A real comparison from your life, with 2 to 4 options and 3 to 5 criteria: subscriptions, quotes, devices, courses, routes.

Gather your information, with the source and date of each price.
Ask for the table with your columns, the common unit and the “not specified” rule.
Redo the calculations that decide your choice.
Ask for the opinion separately, with your own criteria.

Check your work

It worked if:

every number in the table comes from your notes or from a dated source;
costs are in the same unit, and you redid the important calculations;
missing information says “not specified”, instead of an invention;
the recommendation is separate from the table, and rests on your criteria.

Common mistakes:

comparing prices per month, per week and per year without converting them;
letting the AI choose the columns: it picks general criteria, not yours;
believing a total without redoing it;
keeping a price without its date: a rate changes, and your table gets old.

Keep it and pick it up later

Store your comparison request in your library, with brackets for [the options], [the columns] and [the unit].
Keep the final table with the date of each price.

Going further

optional

Claude can also create an Excel file (.xlsx) directly, with its formulas, which you download. Then check the formulas, the way you checked the calculations. According to Claude’s help (24/10/2026), file creation is open to all plans, in principle turned on by default on Free, Pro and Max, but not available in an incognito chat in the new version of Claude. If Claude refuses, check the “Code execution and file creation” setting in “Settings”, then “Capabilities”.
Add a “source and date” column: your table becomes checkable by someone else.

New words

5 words explained

Word	What it means
Comparison	A table that puts options side by side, criterion by criterion
Criterion	What matters for your decision: price, length, commitment, hours…
Common unit	The same way of counting for all options: per year, per month, per person
CSV	A simple text table format that every spreadsheet can open
Spreadsheet	The software for tables and calculations: Excel, Google Sheets, LibreOffice Calc, Numbers

Date, version, sources Written on 24/10/2026. The method in this lesson works with any assistant. File creation of Excel files by Claude: support.claude.com, “Create and edit files with Claude”, read on 24/10/2026. Calculations in the example redone on 24/10/2026. To be checked: opening the CSV file has not been tested in every spreadsheet.