Personal experience – How to prepare for a mental arithmetic test

Preparing for an upcoming mental arithmetic test involves unique strategies, and while everyone has their own approach, I’d like to share my personal experience. Many trading firms, including well-known ones like Optiver, incorporate mental arithmetic tests in their interview processes, often showcasing these tests at career events for practice.

As you read the last sentence in the previous paragraph, did you feel a surge of stress at the thought of on-the-spot pressure, or did you perceive it as an exciting challenge? Your mindset here sets the tone for your preparation. Instead of viewing the test as a mere assessment, see it as a stimulating challenge, even a fun activity. Remember, mental arithmetic is a skill that can be trained; nobody is born as a human calculator—it’s all about practice.

So, where do you start? First, understand the test’s format. What kind of questions will it include? Will there be decimals, fractions? How fast must you respond on average? Such knowledge helps tailor your practice effectively. Take the Optiver math test, for example, which has 80 questions that need to be answered in 8 minutes, averaging 6 seconds per question. However, it’s a common error to assume that you can spend 6 seconds on each question. Realistically, you’ll need a second to read the question, another to review the multiple-choice answers, and a third to mark your response and move on. This effectively leaves you with about 3 seconds per question.

Knowing the required speed, how do we achieve this? Focus on two aspects: speed with accuracy and consistent performance over the full duration. This involves maintaining concentration and managing pressure.

Speed and Accuracy

This is fundamental yet only the initial step. Begin by practicing on an easy level for two-minute intervals. You should be so familiar with multiplication tables that, for instance, 7×8, instantly equates to 56 in your mind. When encountering more complex calculations like 17×18, instead of laborious step-by-step computation (10×18 + 7×10 + 7×8 = 306), learn shortcuts (20×17 – 2×17 = 306). Aim for answering each easy question within two seconds; this will set a solid foundation.

Create your own mental math test and focus your preparation on very specific types of questions with our Mental Math Practice tool.


Here, vary your training with longer durations, like 4 or 8 minutes, without letting your average time per question increase. Utilize tools to monitor your progress and consider practicing in noisy environments to enhance your focus. Our mental math tools provide you with all the necessary tools you need to prepare yourself. Remember, conditions during the actual test might be less than ideal, so you need to train yourself on keeping your concentration under less ideal situations (loud environment, for example).

Performing Under Pressure

My preparation became particularly intense at this stage. For instance, training the morning after a night out with friends, amidst a hangover, may seem extreme, but it’s effective. Practicing in challenging conditions—whether it’s in a bustling cafe or at a lively family gathering—prepares you for maintaining performance even when conditions are not optimal. This type of training proved invaluable for me; despite feeling under the weather during my actual test, I excelled.

Such comprehensive and intense preparation might seem over-the-top, but it equips you to handle any situation, ensuring you’re ready for the test regardless of circumstances.