UDFs in VCE General Maths: from optional shortcut to near necessity?

I graduated from VCE in 2023, and I got through General Maths without using UDFs.

At the time, I didn’t think much of it. They felt like an optional extra, something useful, but not necessary.

My first real exposure to them came later, when I started tutoring. I would watch some of my students fly through long, painful networks questions and get correct answers in seconds using nothing but their CAS calculator. Meanwhile, the same questions would normally take other students much longer and leave far more room for human error.

For as long as possible, I put off properly learning how UDFs worked. I did not want to admit how powerful they were.

Now, after seeing them in action over and over again, I think it is pretty hard to deny the truth: UDFs can do almost everything for you. In some areas of General Maths, you barely need to think through the content in the same way anymore. The subject can start to feel less like solving maths problems and more like entering the right information into your CAS and letting it generate the answer for you. On top of that, the chance of those dreaded human errors drops dramatically.

This issue is not exactly underground anymore either. It has already been picked up in mainstream media, including a Herald Sun article about calculator programs giving some students an unfair edge in VCE maths exams.

People are waking up to UDF use.

And more importantly, it really seems like VCAA is too.

What Changed in the 2025 Exam

One thing I have always found about General Maths is that VCAA can be incredibly repetitive. Question styles tend to come back again and again, often with only minor changes. Once you know the patterns, the exam becomes much more predictable.

That is why the 2025 General Maths exam stood out so much. It felt noticeably different from previous years.

The questions were less routine, more unusual, and in many cases more challenging than what students had come to expect based on past exams. On the evening after the exam, my Happy Brain students and I were all talking about it in our class Discord because we were genuinely shocked by how different it felt.

That exam really made me stop and think. It felt like a sign that VCAA was already trying to move away from the overly repetitive style that makes UDF use so powerful.

Why SACs Are Shifting

This year, my General Maths students have started sitting their SACs, and I keep hearing the same thing from different schools.

They are being asked not just to answer questions, but to give much longer written explanations of their reasoning as well. In many cases, this has taken the form of an “investigation” task, where students need to include things like an aim, a method, reasoning throughout, and a conclusion.

At first, I thought this might just be something one school was trialling.

Then I heard about it from another school.

And another.

And another.

Very quickly, it stopped looking like a coincidence.

From what I understand, VCAA raised this kind of approach in a webinar for schools at the start of this year. If that is the case, then the message is pretty clear: they are looking for ways to make SACs less vulnerable to pure UDF dependence and more focused on interpretation, reasoning, and communication.

In other words, they are trying to combat the way UDFs can bypass large parts of the thinking process.

What VCAA Is Planning Next

The third major sign is the survey.

A student of mine pointed me to a post on mathematicalcrap, which discusses a survey VCAA asked teachers to complete. Alex Blanksby also discusses this issue in his Substack article, It’s time to talk about CAS calculator programs.

According to these discussions, VCAA launched a short survey about CAS use, including the possibility of putting CAS calculators into a “restricted mode” for the 2027 VCE exams.

That is a very big deal.

Now, realistically, VCAA cannot suddenly ban CAS calculators altogether, and it is highly unlikely that they would impose a major change like restricted mode on students sitting the 2026 exam without proper lead time. Any major change would more likely come alongside the next study design.

But even if restricted mode is not immediate, the direction of travel seems obvious.

VCAA is paying attention.

They know UDF use is widespread.

And they appear to be actively thinking about how to reduce its impact.

What This Means for the 2026 Exam

Because of all of this, I would not be surprised if this year’s General Maths exam looks very different from the older papers students are used to practising.

If VCAA is serious about reducing the power of UDFs, then we can expect exams that are:

• Less repetitive
• Less predictable
• Less easily bypassed through memorised calculator workflows
• More focused on interpretation and reasoning

The problem is that this creates a really awkward reality for students right now.

Even if VCAA is trying to fight back against UDF use, students who do not use them are still at a major disadvantage under the current system.

Alex Blanksby gave a great example of this in his discussion of Question 39 from the 2025 Exam 1, where he noted that a UDF made the problem almost trivial, while students without it had to spend much longer solving it manually for the exact same one mark.

That is the issue in a nutshell.

Even if VCAA wants to reduce the influence of UDFs, they are still incredibly powerful right now. So until the system changes properly, students who choose not to use them are often the ones being punished.

What This Means for You

So, where does that leave students?

Honestly, I think the best thing you can do right now is learn how to use UDFs.

I hesitate to even call them an “advantage” anymore, because VCAA’s recent actions make me think they are becoming closer to a default requirement for high performance than just a bonus shortcut. That may not be how the subject is supposed to work in theory, but it is increasingly how it works in practice.

That does not mean students should avoid learning the actual maths. If anything, strong understanding matters even more if exams become less predictable.

But right now, going into General Maths without UDF familiarity is, in my opinion, putting yourself at a serious disadvantage.

• Learn core UDFs early
• Practise questions both WITH and WITHOUT them
• Focus on reasoning, not just inputs

What We Are Doing at Happy Brain

At Happy Brain, we are making this a priority. We’re solving this exact problem for you.

We want to make sure our students are not left behind when it comes to CAS programs and UDF familiarity. A lot of the resources we are planning will be free and publicly accessible, so if this is something you want help with, keep an eye on our Instagram for updates.

Already, our amazing Math Methods Course Lead has created a detailed series of LMS videos explaining how to use each UDF in Methods.

And soon, General Maths resources will be coming too.