Maths teacher shares his fx-CG50 strategies for A-level exams

Believe it or not, there are just a couple of months to go until exam time. That means GCSE and A-level maths students and teachers across the country will be busy using all of the tools at their disposal to aid revision and reinforcement of key skills and knowledge.

We recently spoke to James Davis, Associate Assistant Headteacher and Maths Teacher at Newstead Wood School, about the methods he uses at this time of year, with a focus on how the fx-CG50 graphic calculator supports his teaching and student understanding.

Here are some of the key talking points from our conversation.

Hammering home the fundamentals

Starting with the basics, James ensures he uses the fx-CG50 in every lesson, taking advantage of the emulator to display his screen to the entire class and reinforce those fundamental calculator skills.

He also works through past exam questions to give some context to how the handset can be used in practice and how valuable it is for checking work and boosting understanding.

Crucially, the mark scheme is presented alongside the question, giving students a clear view of how important it is to show their working process so they don’t miss out on method marks.

Using the calculator in every lesson also provides lots of opportunities for James to remind students of how they can benefit from its most useful functionality, such as graphing and the SolveN tool.

“SolveN is very powerful, because it finds solutions to equations that have numerical answers – including linear, quadratic, trigonometric and simultaneous equations – provided the student has been taught well and actually knows how to solve them,” James said.

An effective tool for checking work

Being able to check their working as they’re moving through a multi-stage exam question is a vital skill for A-level maths students, and this is an area where the calculator can prove extremely useful.

Reiterating how crucial it is for students to demonstrate their understanding by showing accurate working, James gave some examples of practices he uses in lessons.

He encourages students to take a moment at the midway point of long questions to check they haven’t made any simple errors and that they’re on the right track. One example of how to do this is by using the fx-CG50’s graphing functionality to verify that two expressions are equal.

If they come across a trigonometry problem asking them to show that a cos x + b sin x = R cos(x − α), for example, students can get a lot of help from Graph mode.

“By plotting the two graphs – the original one and the one they have halfway through the question – students can check they’re equal and that they’ve got the right answer,” James said. “If the expressions aren’t producing the same graph, they can look at what changes are needed to get back on the right track.”

Take advantage of the Distribution app

Another tool that James has found particularly useful, and that his students have really taken to, is Distribution mode. You’ll find this on your handset if you’re running OS 3.6 or later, and it’s definitely worth updating your operating system if you don’t currently have access to Distribution.

One of the key benefits of this app is that it centralises a range of functionality for calculating and viewing probability distributions. It also removes the need to remember syntax, and has the capability to visualise both discrete and continuous distributions as a graph.

“I’m a big fan of the Distribution app on the fx-CG50 and my students are really liking it as well,” James said. “It’s very powerful, and I’m finding it increasingly useful for things like critical regions of binomial distributions, partly because it’s more visual than Statistics mode and helps to save time.”

He also noted that exam boards expect candidates to show that they can do basic statistical calculations such as mean and standard deviation on a calculator, so there’s no need to write out the long-winded and time-consuming sums that some students still rely on.

Lesser-known features of the fx-CG50

When it comes to the benefits and functionality of the fx-CG50 that some users might not be aware of, or could potentially use more, James highlighted the VARS key, which recalls variable data.

This comes in useful when students need to save values from equations or calculations and use them in other modes on the handset. It removes the need to write things down or remember them, and also helps to avoid rounding errors, which can creep in when working with numbers with several decimal places.

James also made a suggestion that could help students in exam questions that ask them to find the equation of a tangent at a given point. Turning on Derivative mode will allow them to plot a graph and then use the tangent functionality – accessed by pressing F4 – to view the tangent and get the values they need.

“That’s a lesser-known feature and probably one of the most powerful ones for students to be aware of,” he added.

If you’re interested in taking a deeper dive into the fx-CG50 and its full range of functionality, pay a visit to our resources centre. Here you’ll find videos on extracting X-values from the Distribution app, sketching the tangent to a curve and much more.