Seb Bicen’s top tips for using the fx-CG100 in exams

The fx-CG100 graphic calculator is designed to support students through some of the trickiest parts of GCSE and A-level maths. But the best insights into how it actually helps in the exam hall often come from the teachers using it every day.

We spoke to Seb Bicen – an experienced maths teacher whose YouTube channel has over 116,000 subscribers – about the practical ways the fx-CG100 helps his students work more accurately and efficiently.

Building familiarity with the fx-CG100

Seb noted that, for students using the fx-CG100, it’s the key tool they can actually rely on when it matters most. As he puts it: “It really is just the most useful piece of technology that they’re going to have access to and that they can also use in exams.”

That’s why he encourages students to weave it into their studies from day one, rather than treating it as something to pick up closer to exam season.

He compares getting to grips with it to any new device you might own. “You get a new piece of tech and at first you’re like, ‘Oh, the old one was much easier!'” he says. “But when you’ve been using something new for a little while, you naturally get speedier and you know where everything is.”

Familiarity with the calculator pays off in a very specific way. In Seb’s experience, some of the most common frustrations for students are making small input errors under pressure, mistyping something or missing a step in how it’s entered.

The solution to this is simply regular use and practice. The more comfortable students are with the fx-CG100 before exams, the more muscle memory they build up and the less room there is for these avoidable slips to creep in.

Getting the most out of the fx-CG100

Once the basics feel natural, Seb points to a few specific ways the fx-CG100 can genuinely change how students approach exam questions.

Verifying tangents to a curve

One of the most common types of question in A-level maths exams involves finding the equation of a tangent to a curve. Rather than just trusting the algebra, students can plot both the curve and their calculated tangent line on the fx-CG100 and see for themselves whether the line touches the curve at exactly one point.

“It’s nice to have such a visual way of doing it – you can see that you’ve got this curve and this line just touching it at one point,” says Seb.

The fx-CG100’s graph analysis tools can add a further layer of confirmation, showing how many times the two lines actually cross. If it shows two intersections rather than one, that’s an immediate sign the tangent equation needs another look.

“It’s a nice reassurance that you’ve got it right,” Seb adds, as it gives students the confidence to move on rather than second-guessing their working.

Saving time with statistics and distributions

Another key feature of the fx-CG100 is the Distribution app, which allows students to enter a double inequality directly – finding the probability that x falls between two values in a Binomial distribution, for example – in a single step.

“It’s a huge timesaver in the exam,” Seb says, adding that it can remove the need for a multi-stage calculation where small errors can easily creep in under time pressure.

Alongside this, the visual representation of a probability distribution helps students build a clearer picture of what the numbers actually represent, so accuracy and understanding reinforce each other rather than working in isolation.

Tackling longer problems

The fx-CG100 also provides distinct advantages for those longer, multi-step questions that appear in exams and can prove stressful for students. The Calculate app keeps a running, scrollable record of every calculation performed, offering a clear view of previous steps and outcomes.

Seb encourages students to let this build up throughout a question rather than clearing it, so that if something goes wrong, they can scroll back and spot exactly where it happened.

“It can work kind of like a digital pen and paper,” he says, providing a visible trail of thinking that sits alongside written work rather than replacing it.

This is where the fx-CG100’s larger display really earns its keep. Rather than a single line or two of calculation disappearing the moment they press EXE, students can scroll back through everything they’ve worked out for a question, all still visible on screen.

For Seb, this is one of the most valuable things about the calculator: it means nothing gets lost in the background. Students always have a full picture of how they arrived at a solution, not just the answer itself.

Building good habits with the fx-CG100

Alongside regular practice, Seb also recommends habits like activating UK Exam Mode before class tests or mocks. A dedicated app means this is a quick and easy job on the fx-CG100.

As Seb points out, rehearsing it in advance helps to avoid any unnecessary stress on the day of the real exam, simply as a result of having done it so many times before.

That same regular use also helps students become familiar with the calculator’s everyday advantages. The colour screen, for example, makes graphs clearer to read and interpret, making it easier to spot key features when working through problems.

More from Seb Bicen

For more practical guidance on using the fx-CG100 for A-level maths, you can watch Seb’s dedicated video: How to use the Casio fx-CG100 graphics calculator.

It walks through some of the handset’s most useful features in more detail, including finding the intersections of two curves, solving simultaneous equations, and working with trig equations in both degrees and radians.

It’s just one of many videos on Seb’s channel, which also features deep dives into the topics that make up the A-level maths curriculum, from forces and motion to binomial hypothesis testing, and everything in between.