Professor Pi is named after the most famous irrational number in school maths because, well, the joke writes itself. But the name also signals something specific: Pi cares about elegance, about the structure under the symbols, about why a method works. Not just whether your child got the right number out.

This article is the long-form introduction. Pi is the agent most KS3 students will spend the most time with on aitutors.me, and the agent whose design choices I'm most opinionated about. If you skim only one paragraph, make it the next one.

The single decision that defines the whole tutor

Pi refuses to give answers on first request. Not as a feature toggle. As a hard architectural commitment.

If a Year 8 child types "What's x in 3x - 5 = 10?" into Pi, the response is not "x = 5". It's a question back: "Show me your working — what did you do first?"

This is the opposite of how every general-purpose chatbot behaves. ChatGPT, Claude, Gemini — given a school maths question, they'll cheerfully produce a fluent, well-laid-out, often correct solution. Which is exactly the problem. The thing your child needs to learn is the process. Handing them the product trains them to outsource the process.

I watched this happen with my own Year 8. Within six weeks of free-text-prompting a homework helper, the same misconceptions kept recurring, fluently expressed and entirely uncorrected. Pi is the response to that.

What KS3 territory Pi covers

Pi sits exactly on the KS3 national curriculum and the AQA / Edexcel schemes of work most UK secondary schools follow. So:

  • Number: place value, fractions, decimals, percentages, ratio, indices
  • Algebra: notation, expressions, expanding, factorising, linear equations, sequences, simple inequalities
  • Ratio & proportion: percentages of amounts, scaling, direct and inverse proportion
  • Geometry & measure: angle facts, polygons, area, volume, transformations, Pythagoras (Year 9)
  • Statistics & probability: averages, scatter graphs, simple probability, sample space diagrams

Where a school topic has a Year-by-Year cadence (Year 7 introduction → Year 8 deepening → Year 9 fluency), Pi tracks it. A Year 7 doing expanding brackets gets a different scaffolding than a Year 9 doing expanding double brackets, even though the concept is the same family.

Where Pi sits among the maths tutors

There are two maths-shaped agents in the aitutors.me faculty, and people get them confused. Quick map.

Agent Job Material
Professor Pi KS3 curriculum mastery Years 7–9 national curriculum
Professor Abel Competition strategy UKMT JMC / IMC / olympiad style

Pi makes sure your child understands the maths their school is teaching. Abel makes sure your child can win at the kind of puzzle the school day rarely contains. The two share notes — Abel reads what Pi has covered before pushing competition problems — but their goals are distinct.

If your child is comfortable in school maths and wants stretch, Abel is the right next step. If your child finds school maths a slog, Pi is where the work needs to happen first. Don't skip the foundations to chase the puzzles.

The shape of a Pi session

Every Pi session opens after the Mentor has cleared the energy gate (see the energy protocol). Pi receives the energy colour and mood, and adjusts.

A typical 25-minute session on a normal-mood GREEN week:

  1. Read the progress file — what's the student's current mastery on this topic, what misconceptions has Pi seen before?
  2. Warm-up problem — confidence check, usually a topic the student has already done well on
  3. Spaced review choice — Pi offers any due review items as warm-up, and respects "skip for today" without sulking
  4. Main work — one or two topics, three-to-six problems, escalating difficulty
  5. Confidence rating — 1-to-5 on the main topic, captured silently
  6. Brief close — no lecture, no homework, no streaks

The shape changes with energy. AMBER + tired collapses the session to ten minutes of light review. GREEN + high opens up extension problems and the occasional cross-subject hint.

Three things Pi insists on

There are three behaviours Pi will not skip, regardless of energy or topic.

1. Show your working

Before Pi marks anything wrong, it asks to see the working. This is the Show Your Working protocol — the topic of its own article. The reason in one sentence: a wrong answer with working tells Pi exactly which step broke, and most break-points are recoverable with one targeted hint.

2. The hint ladder, not the answer

The four-level hint ladder is the core engine — see the dedicated article. It is the structure that makes "refuses to give the answer" survivable. Hints get progressively more specific. The answer only comes after sustained struggle.

3. Misconception probes

Before teaching a topic, Pi asks a short probe to surface misconceptions. "Does multiplication always make numbers bigger?" is the classic one — a child who says "yes" needs the conversation about fractions less than 1 before any new topic is worth attempting. Probing first is the difference between teaching and *re-*teaching the same gap nine months later.

What Pi explicitly does not do

A short list of things Pi refuses, on purpose.

  • Auto-completing homework. If you paste a worksheet, Pi works through it problem by problem with you, not for you.
  • Giving the answer to a school assessment. If Pi detects exam-paper language, it backs off and points you towards the school's mark scheme conversation.
  • Streak-shaming. No "Day 14, don't break it!" prompts. Pi is run by the Mentor's protocols, which are explicitly designed against streak addiction.
  • Pretending to be human. Pi is an AI. Asking "are you a real person?" gets a clear answer.

What's under the hood (briefly)

Pi runs as an MCP server on Anthropic Managed Agents, using the Claude model family. The system prompt is around 600 lines, the pedagogy skill is shared with the other tutors, and the student-context skill is generic — no personal data hardcoded. The full PRD is on the repo if you're the kind of parent who reads PRDs (some of you are, I love you for it).

A note from the parent who built it

I built Pi because I have a Year 8 child and I'd seen enough general-purpose chatbots be net-negative for her maths to know that the off-the-shelf version doesn't work. Pi is the version where someone — me, in this case, with the help of about two thousand UKMT problems and the Carnegie Learning MATHia research — has actually thought about what a maths tutor should be doing, and built the agent to do that, and refused to ship the agent that does the easier thing.

It's better than the alternative. It's not as good as a brilliant human one-to-one tutor. £14 a month is the price point at which "better than the alternative" matters.

Jason runs aitutors.me. He has a Year 8 child and around fifteen years of building software adjacent to education. Updated 21 May 2026.