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Skills / Spreadsheet basics

Spreadsheet basics

Build spreadsheet fluency on data they already track. Structure, formulas, lookups, and summaries on their own sheet. Use when they say "teach me spreadsheets", "help me with Sheets/Excel", or bring data living in their notes app.

Use this skill. Nothing to install.

Open in ChatGPT Open in Claude prefilled and ready; just hit send
for Gemini, Copilot, or Cursor: paste it, then say "use the spreadsheet basics skill"

Don't have an agent?  ·  Raw file: skills/spreadsheet-basics.md

Watch the first two minutes

This is how a session starts when someone has never built a sheet of their own. Click through it.

​(pastes the skill) teach me spreadsheets. everyone at work uses them and i just nod along
We can fix the nodding today. First question: what do you already keep track of, even loosely? Grades, match results, money in and out, workouts, a collection. Anything with rows in it.
i log my climbing sessions in my notes app. maybe 30 entries
That's our dataset. Ten real rows beat a hundred invented ones, and you have thirty. Moving them into a sheet is the first lesson, because it forces the structure conversation: one row per session, one column per fact.
can't you just generate demo data? my notes are embarrassing
No demo data while yours exists. Every formula I show you will answer a question you actually have about your climbing. So tell me one: what do you want this sheet to settle?
whether i'm actually getting better or just going more often
A sheet can answer that. We'll build a summary block: sessions per month next to hardest grade per month. Before every formula you'll predict the result out loud; the wrong guesses are where the learning happens.

Scripted example of a real session.

Have nothing worth putting in a spreadsheet?

Almost nobody thinks they do, and almost everybody does. The skill starts by asking what you keep track of loosely: in a notes app, in a group chat, on paper, in your head. It picks whichever has the most rows and builds from that. If the data only exists on paper, entering it together is the first lesson. If you genuinely track nothing yet, start a small project that produces rows:

Count something for a week Game night standings A week of logs

What you end up with

The same thirty climbing sessions, before and after. The before lived in a notes app; the after is a sheet that answers the question it was built for.

Example
BEFORE  ·  NOTES APP
tues climbed at crux, purple v3 finally!!
went again thurs. tired. mostly v1s
sat w/ dana, tried the v4 overhang, no
AFTER  ·  SESSIONS TAB 1
date        gym     hardest  attempts
2026-05-02  Crux    V3       14
2026-05-04  Crux    V1        9
2026-05-07  Boulda  V3       11
SUMMARY BLOCK 2
month     sessions  hardest
2026-03   6         V2        =COUNTIF(...)
2026-04   7         V3
2026-05   6         V4
Answer: hardest grade climbed rose from V2 to V4 over three months while sessions per month stayed flat 3
  1. One row per session, one column per fact. Header frozen, dates typed as dates, numbers as numbers. The skill shows you what breaks when "3 wins" sits in a number column.
  2. Formulas you typed yourself. SUM, COUNTIF, a lookup across tabs, then a summary block. Each one arrives when a question of yours needs it.
  3. The answer as a sentence at the top of the sheet. The summary now says something the raw rows did not, and adding a new session updates every number.

Questions people actually ask

Is this free?

The skill is free. It works in Google Sheets or LibreOffice Calc, both free, whichever you already have.

Excel or Google Sheets?

Whichever is in front of you. The session uses Google Sheets or LibreOffice Calc, and everything it teaches (SUM, COUNTIF, lookups, a summary table) works the same way in Excel.

Do I have to memorize formulas?

No. Each function is introduced the moment one of your own questions needs it, never as a list to memorize. You type every formula yourself and predict the result before pressing enter.

My data is on paper or buried in a group chat.

Then entering it is the first lesson. Typing it in forces the structure decisions (what is a row, what is a column) that make everything after it work.

What happens when I get new data next week?

You add a row and watch every summary update. That is the finish line of the session: a sheet where new data flows through without you rebuilding anything.

Where to go from here

Sheet built? The natural next skills:

Clean a dataset Chart the truth Track anything

Want a project that runs on a sheet?

Club dues tracker Your season in numbers A year of books
Curious? Read the full skill — the exact instructions your agent gets 
---
name: spreadsheet-basics
category: data
description: Build spreadsheet fluency on data they already track. Structure, formulas, lookups, and summaries on their own sheet. Use when they say "teach me spreadsheets", "help me with Sheets/Excel", or bring data living in their notes app.
---

# spreadsheet-basics

Teach spreadsheets to someone who has probably only seen
them as grids other people fill in. The way in is their own data:
something they already track in a notes app, a group chat, or their
head. Use Google Sheets or LibreOffice Calc, whichever they have.
Every formula you introduce answers a question they actually asked.

## Find the data first

Ask what they keep track of, even loosely: grades and assignments,
match results for a game they play, money in and out, workouts, a
collection, hours at a job. Pick the one with the most rows in it.
Ten real rows beat a hundred invented ones — never make up demo data
when their own exists. If the data is on paper or in messages, entering
it together is the first lesson: it forces the structure conversation.

## Structure before formulas

Build the sheet with them, talking through each choice:

- One row per thing that happened, one column per fact about it.
  Header row, frozen. No merged cells, no color-as-data.
- Each column holds one type: dates formatted as dates, numbers as
  numbers. Show what breaks when "3 wins" sits in a number column.
- If two distinct entities genuinely exist (games and players, purchases and
  products), give each its own tab. Otherwise keep one data table and avoid
  structure that the real data does not need.

## Formulas that answer their questions

Introduce each function the moment their question needs it, never as
a list to memorize:

1. Arithmetic and cell references — a total or difference column.
   Fill down; show that the reference moves.
2. SUM, AVERAGE, COUNT, MIN, MAX over a whole column.
3. IF for a judgment column: pass/fail, over/under budget, win/loss.
4. COUNTIF and SUMIF — "how many losses?", "how much on food?"
5. If the data has a real second entity, use a lookup to pull one of its facts.
   Otherwise use another formula the person's question actually requires.
6. A summary table: one block, built with UNIQUE + SUMIF or a pivot
   table if the tool has one — totals per category, per month, per
   opponent. This is the payoff: the sheet now says something the raw
   rows did not.

At each step, have them type the formula. Predict the result out loud
before pressing enter; wrong predictions are the best teaching moments.

## Done

- A sheet of their real data with a clean header, typed columns, and only the
  tabs its structure requires
- Working formulas they wrote themselves, including COUNTIF or SUMIF and a
  lookup when the data genuinely requires one
- A summary block that answers a question they cared about, with the
  answer stated in a sentence at the top of the sheet
- They can add a new row and watch every summary update

Then: clean-a-dataset when they meet messier data, or chart-the-truth
to turn the summary block into a chart.