2024-2025 GAMSAT® Online Courses Now Open! | Enrol Now to Get Access to Our Resources Until March 2025

GAMSAT® Calculator

No Calculator...No Worries!

by , 22 March, 2024
Read 492 times

Perhaps you’re reading this post and are new to the GAMSAT Exam. If so, like most of us you’re probably reeling internally from the news that you can’t use a calculator in this monster of an exam. In fact, forget about GAMSAT® calculator, you’re not even permitted to bring in a ruler!
From my experience tutoring GAMSAT® Exam candidates, there are a couple of reasons why people worry over their non-calculator skills. The first surrounds actually being able to do the calculations required by the questions, and the next to do them in the time available.
For many, calculating things by hand is something we haven’t done since early high school. Consequently, I’ve encountered many students who find working without a calculator about as easy as changing a car tyre without a jack. Fortunately, there are a few things I’ll discuss here which you can practise now to ensure this doesn’t hold you back unnecessarily.

Tip #1: Understand Why You’re Not Allowed to Use GAMSAT Calculator

GAMSAT® Course Reopening
First things first, Section III of the GAMSAT® is really the section where you will be required to do some calculations. Check out our other article for an in-detail overview of GAMSAT 2024. It’s helpful to keep in mind here that the Exam has been designed to test your logical thinking skills in the physical and biological sciences and that it’s written with the GAMSAT calculator restrictions (and working out paper limit of two sheets!) in mind. This means that you won’t be tested on complicated mathematical theory, or likewise asked to complete page-long derivations. If it seems that way, you will be approaching the question wrong. Rather, what you’ll need to focus on is being able to do by hand what you would do on a calculator without a second thought.
It absolutely is possible to do all the questions in GAMSAT® Section 3 without a calculator - if it wasn’t, then they wouldn’t put them in the exam! To add some context, some of the things which you’ll need to be able to do for Section III include: computations with fractions and/or decimals, basic geometry and trigonometry, and manipulating exponentials and logarithms. These topics may sound familiar, but it is worth reviewing some of the basic maths skills they entail, particularly if it has been a while (perhaps since Year 9 or 10!) since you last employed such skills.

Tip #2: Practice and Learn Some GAMSAT Math Tricks

Secondly, timing. It’s arguably the biggest mountain you’ll have to climb, as Section 3 of the GAMSAT® contains 75 questions in 150 minutes (of which 8 mins is reading time). So, to even approach this section without a calculator, you’ll need to be experienced at performing calculations and QUICKLY. Check out our other article for an in-depth guide of GAMSAT Section 3.
To reasonably tackle the problem of timing, from the perspective doing the calculations alone, you will need to practise. Certainly, this will help your familiarity with formulas and concepts like scientific notation, yet practice alone usually won’t do the trick. Instead, the key here is to learn what mathematical ‘tricks’ and shortcuts work best for you. If you find yourself unable to perform calculations in less than the 2 minutes allowed, try looking at how others think of the problems and seeing if you can apply someone else’s logic. The worked answers in the GradReady MCQ bank often demonstrate some of these tricks, such as rounding and simplifications. You will come to realise the need to have approximations for constants like pi, e, square root of 2, and get a feel for when to round vs keep an exact answer. Study groups are also a great way to do this (for more on studying in a group, check out our article Group Studying: Pros, Cons, and Tips).
Take every opportunity you can to do calculations by hand and do away with checking things on a calculator once you’ve had a bit of practice. Also, finding ways of performing a quick ‘sanity check’ on your answer - even if it’s just thinking about the magnitude of the value you’ve computed (e.g. Does a negative number make sense here? Should my answer be between 0 and 1?) - will work wonders for your confidence and thereby help you with both your speed and accuracy.
As an example of the importance of maths skills, attempt the following question, bearing in mind the 2min/question time allocation of GAMSAT® Section III:

 No Calculator No Worries

Firstly, always beware the chemical equations given to you.

This one is not balanced (three oxygens on the left side yet two on the right), so we need to balance it to get 2KClO3 à 2KCl + 3O2.

20g of oxygen is equal to how many moles of oxygen? Knowing n = m/M, we can substitute 20/(2 x 16) = 20/32 mol. Note that it is O2 and not just O, so the Molar Mass is double the 15.9994, which should be rounded to 32g/mol.

The ratio of 2KClO3 to 3O2 needs to be noted, so we need only 2/3 of the 20/32 mol of KClO3. Recall the rules for multiplying fractions, this is 40/96 mol, which is probably close enough to 40/100 that we can round it to this, bearing in mind the answer options are reasonably spread apart. If instead the answers were very close together, we would need to be more precise with our rounding.

So we want 40/100 or 0.4 mol of KClO3, which has Molar Mass of 39 + 35.5 + 48, which we can sum exactly or round again to 40 + 35 + 50 = approx 125 g/mol.

Again, n = m/M, so substituting we have 40/100 = m/125. Rearranging, we get m = (40/100) x 125. This is the same as (125/100) x 40, which is (5/4) x 40 = 5 x (40/4) = 5 x 10 = 50g. Thus answer A is the correct choice!
This question clearly demonstrates the need for not only your chemistry knowledge (balancing equations, using rules for amount like n =m/M, stoichiometric ratios), but also the maths skills required to compute the answer. While converting fractions to decimals and performing basic operations like multiplication and addition should be familiar to everyone who completed primary school (!), often students are out of practice when it comes to using these skills under exam pressure. Thus, it is vitally important to do lots of practise questions ahead of the real thing!


The non-calculator edict of the GAMSAT® Exam is a challenge for all, however with the above in mind you can reasonably work to put yourself in a position to tackle problems with confidence and accuracy. Practise as many of these calculation type questions as you can ahead of GAMSAT® test day, refamiliarising yourself with old skills, and picking up on the many tricks and simplifications needed to complete these questions on exam day.

If you find tackling Section 3 without a GAMSAT® calculator to be a challenge, and specifically the calculations in the Physics section which many student struggle with, check out our guide GAMSAT Physics: How to Prepare