Immediate result: The exact formula for Excel or Google Sheets, explained, with an example of the output.
Problem it solvesYou know what you want the spreadsheet to do but not the formula, and nested IFs break.
Google Sheets: total of column C where column A is 'Mumbai' and column B is in October 2026
=SUMIFS(C:C, A:A, "Mumbai", B:B, ">="&DATE(2026,10,1), B:B, "<"&DATE(2026,11,1))
Each pair is a condition: city = Mumbai, date ≥ 1 Oct and < 1 Nov.
Error #VALUE! usually means column B holds text, not dates.
You know what you want the spreadsheet to do, but not the formula, and nested IFs keep breaking. This skill picks the simplest function that works — XLOOKUP, SUMIFS, FILTER, LET or QUERY — and writes it for your exact cell references in Excel or Google Sheets. It explains each part, shows the result on a small example and lists the errors you're likely to see with their fixes. If a function isn't available in older Excel versions, it says so and gives an alternative that works. To use it, paste the skill into your assistant and send what you want to calculate, your column layout (e.g. A = date, B = amount) and Excel or Google Sheets.
# Skill: Spreadsheet formula helper
You are running the "Spreadsheet formula helper" skill for me. I work as: Analyst or Excel / Sheets user. What I need from you: the exact formula for Excel or Google Sheets, explained, with an example of the output.
## When I send you what I want to calculate, my column layout (e.g. A = date, B = amount) and Excel or Google Sheets
1. Pick the simplest function that works (XLOOKUP, SUMIFS, FILTER, LET, QUERY).
2. Write the formula for the cell references given.
3. Explain each part.
4. Show the result on a small example table.
## Reply in this format
- Formula (code)
- How it works
- Example
- Common errors and fixes
## Rules
- Say if the function isn't available in older Excel versions and give an alternative.
- Use only the facts I give you; mark anything you had to assume with [ASSUMPTION].
- If something essential is missing, ask me one short question, then continue.
- No preamble or filler: start with the result.
Confirm you're ready in one line, then wait for me to send what I want to calculate, my column layout (e.g. A = date, B = amount) and Excel or Google Sheets.Then sendWhat you want to calculate, your column layout (e.g. A = date, B = amount) and Excel or Google Sheets. For example: Google Sheets: total of column C where column A is 'Mumbai' and column B is in October 2026
Upload it to Claude, add it to ChatGPT's Codex app, clone it into Claude Code, or download the SKILL.md for any agent. Full guide with screenshots →
Download the ZIP and upload it in Claude. Claude then uses the skill on its own whenever a request matches.
Download ZIP
OpenAI's Codex app reads the same SKILL.md format. Copy the skill into your Codex skills folder:
$ git -c http.version=HTTP/1.1 clone https://scienceofapps.com/skills/ai-skills.git
$ cp -r ai-skills/spreadsheet-formula-helper ~/.codex/skills/
Clone the library and copy this skill into your Claude Code skills folder.
$ git -c http.version=HTTP/1.1 clone https://scienceofapps.com/skills/ai-skills.git
$ cp -r ai-skills/spreadsheet-formula-helper ~/.claude/skills/~/.claude/skills/ for all projects, or .claude/skills/ inside one project.Download the skill file and put it in a folder named after the skill.
Download SKILL.md~/.claude/skills/spreadsheet-formula-helper/SKILL.md.Repositoryscienceofapps.com/skills/ai-skills.git · all 200 skills, one folder each, plain git over HTTPS
You know what you want the spreadsheet to do but not the formula, and nested IFs break. The skill fixes that: the exact formula for Excel or Google Sheets, explained, with an example of the output.
Copy the skill and paste it as the first message of a new chat, then send your input. To keep it, paste it into a ChatGPT Project or custom GPT, a Claude Project or a Gemini Gem, or upload the SKILL.md file as a Claude Skill.
Send what you want to calculate, your column layout (e.g. A = date, B = amount) and Excel or Google Sheets. If something essential is missing, the skill asks you one short question and then continues.
Yes. It's free to copy, use and adapt, with no sign-up, and works in the free versions of ChatGPT, Claude, Gemini and Copilot.
ProblemTeams call A/B tests on gut feel, ship false winners and miss real ones.
Control 10,000 visitors / 400 sign-ups · Variant 10,000 / 460 · 14 days
CR: 4.0% vs 4.6% · lift +15%
z ≈ 2.09, p ≈ 0.037 · 95% CI for difference: +0.04 to +1.16 points
Verdict: likely winner — ship, and watch week-two retention.
Immediate resultA plain-English verdict with lift, confidence interval, p-value and whether the sample is big enough.
ProblemA messy export has duplicates, mixed formats and blanks, and cleaning it by hand is error-prone.
pandas · columns: name, phone, city, signup_date (formats: 03/10/26, 2026-10-03, '3 Oct')
signup_date: 3 formats → pd.to_datetime(df.signup_date, dayfirst=True, format='mixed')
city: 'Bombay'/'Mumbai '/'mumbai' → strip, title-case, map Bombay → Mumbai
Check: rows before = rows after + duplicates removed (logged).
Immediate resultA step-by-step cleaning plan with the code (pandas, SQL or spreadsheet steps) to do it.
ProblemDashboards get built with every metric and answer no question.
Weekly dashboard for the head of a food-delivery city team
Q1: Are we delivering on time? → On-time rate = orders delivered ≤ promised ETA ÷ delivered orders
Chart: line, 8 weeks, with target line at 92%
Filter: zone, hour of day.
Immediate resultA dashboard spec: the questions it answers, metrics with definitions, charts, filters and layout.
All 14 data & analytics skillsAll 200 skillsRead it in the articleProve it: AI for Data Analysts Certification (free test)
60 research-backed principles in 6 categories — what each one means, why it works on the human brain and how to use it on your own screens. Written by Sushant Singh, founder of Science of Apps, who has scaled consumer apps to lacs of users and spent 10+ years leading product across startups and digital businesses in the US, EU & India.
110 real paywalls from top apps, taken apart, rated out of 5 and decoded with the Laws of UX — plus the frameworks, copy and checklists to ship your own. By Sushant Singh, founder of Science of Apps.