Computational and Algorithmic Thinking: The CAT Guide

Computational and Algorithmic Thinking is the competition that most usefully answers one question: can this student reason algorithmically, regardless of whether they have ever written a line of code?

One hour, no programming

The paper is run by the Australian Maths Trust alongside its mathematics competitions, and it lasts one hour.

The defining feature is that it requires no programming at all. Questions describe a procedure, a rule or a situation in plain language and ask the student to work out what it produces, how many steps it takes, or which arrangement satisfies it. Answers are multiple-choice and short answer, written on paper.

That single design choice is what makes the competition valuable. A school can enter its whole cohort without having taught anyone to code, and a student who has never programmed competes on genuinely equal terms.

What it actually tests

Computational and Algorithmic Thinking asks for the habits that underlie programming rather than its syntax.

Tracing a procedure precisely. Given a rule applied repeatedly, what is the state after n steps? This is debugging in disguise, and students who are careless here are the ones who later cannot find their own bugs.

Systematic search. Enumerating possibilities without missing any and without counting any twice. The paper rewards a student who organises their search rather than guessing.

Recognising structure. Spotting that a large problem reduces to a small one repeated, which is the intuition behind recursion long before a student meets the word.

Reasoning about efficiency. Noticing that one method takes many more steps than another, which is complexity reasoning in informal clothes.

Why it surfaces students schools miss

Schools identify computing talent by looking at who does well in computing lessons, which means they identify students who have had the opportunity to learn to program.

Computational and Algorithmic Thinking cuts across that. A Class 7 student with no access to coding classes, no laptop at home and no prior exposure can score highly, because the paper tests thinking rather than training.

In our experience the students who most benefit from being entered are not the ones the school nominates. They are the careful, methodical students who have never been offered the chance.

Sitting the paper well

One hour is short, and the single most common loss is spending too long on one question.

A student should work through the paper once, answering what comes quickly, and then return. Later questions frequently extend an idea from an earlier one, so reading ahead occasionally solves a problem that looked hard in isolation.

Because questions are multiple-choice and short answer, checking the small cases against the stated rule catches most errors. A student who tests their answer against the first two or three steps of the described procedure rarely submits a wrong one.

Our CAT preparation course works past papers under timed conditions and then spends the review on how the student searched, because a right answer found by luck does not transfer to the next paper.

How it fits the pathway

Computational and Algorithmic Thinking is the stage before a programming olympiad, not an alternative to one.

The reasoning it develops is precisely what the Australian Informatics Olympiad then asks a student to implement in code. A student who sits CAT first and AIO second finds the second step to be about programming, which is learnable in months. A student who attempts AIO first finds it to be about reasoning and programming at once, which is considerably harder.

Internationally the same role is played by Bebras and the Beaver Computing Challenge, both of which are also programming-free. Running one of them in the junior years and CAT in the middle years gives a school a complete entry pathway without a specialist teacher.

For parents: why a paper contest is not a step backwards

Parents sometimes see a no-programming competition as less serious than one requiring code. The reverse is closer to the truth.

Algorithmic reasoning is the part of computing that takes years to build. Syntax takes weeks. A student who can reason and cannot yet code is a few months from being competitive; a student who can code but cannot reason is stuck, and no amount of additional language practice moves them.

That is why the strongest competitive programmers tend to have done a great deal of exactly this kind of reasoning early, and why rushing a child into C++ at nine is usually counterproductive.

What a weak result does and does not mean

A low score on Computational and Algorithmic Thinking does not mean a student should not pursue computing, and treating it that way wastes the information the paper gives.

What a low score usually indicates is that the student has not yet practised working systematically under time pressure. That is a trainable habit rather than a fixed limit, and it responds quickly to being shown how to organise a search and how to check an answer against the first few steps of a rule.

The students who improve most dramatically between one year's paper and the next are frequently the ones who scored poorly first time, because they were missing a method rather than ability.

Practical notes

The paper is sat in school, which keeps the administrative burden low, and the one-hour length fits inside a single lesson.

Because it is offered alongside the Australian Maths Trust's mathematics competitions, a school already entering those can usually add it with no new process.

Year levels, dates, entry fees and the exact question count are set each cycle by the Australian Maths Trust. Confirm the current arrangements before planning around them.