The Quantitative Aptitude (QA) section of the CAT exam is known for its tricky questions that test not just your concepts, but also your calculation accuracy and speed. As a fellow CAT aspirant, I’ve noticed that many of us fall for the same types of calculation traps. In this blog, I’ll break down the ten most common ones—and share how to avoid them. Whether you’re revising the CAT exam syllabus or just starting after submitting your CAT application form, being aware of these traps can give you a competitive edge.
1. Ignoring approximation when allowed
Many questions can be solved faster by using approximation, especially in data interpretation or number-based problems. If you stick to exact values when not required, you waste time.
Avoidance tip: Practice estimating square roots, percentages, and ratios regularly. Learn to quickly identify when options are spaced out enough to allow approximation.
2. Overcomplicating simple arithmetic
Sometimes we turn an easy question into a complex one just because we overthink the arithmetic involved.
Avoidance tip: Stay calm and trust your fundamentals. Look for simpler ways to rearrange the numbers or break down the calculation. This becomes more important as you progress through the CAT exam syllabus and tackle more complex topics.
3. Misreading numbers or symbols
It’s surprisingly easy to read 6 as 9 or misinterpret a minus sign as a plus, especially under pressure.
Avoidance tip: Always double-check your input values. Write numbers clearly if you’re practicing on paper.
4. Not simplifying fractions early
Trying to carry big fractions through the entire problem instead of simplifying them early can lead to messy calculations and errors.
Avoidance tip: Simplify fractions as soon as possible to reduce mental load.
5. Ignoring units and conversions
A classic trap in work/time/speed/distance problems is forgetting to convert units properly.
Avoidance tip: Make it a habit to check units in every step of your solution.
6. Falling for trap options
CAT questions are designed with options that match common mistakes. If your answer is one of them, you might not even realise you’ve made an error.
Avoidance tip: Recheck your approach if you reach an answer too quickly. If your answer matches a very obvious option, pause and verify. This is crucial, especially when practicing with previous year papers that follow the CAT exam pattern.
7. Rounding off too early
Sometimes, we round numbers before the final step and end up with slightly wrong answers.
Avoidance tip: Avoid rounding unless specifically asked. Carry forward actual values till the end.
8. Ignoring the question’s final requirement
You might calculate the correct intermediate value but mark it without reading what was actually asked—for example, marking time instead of speed.
Avoidance tip: Before marking your answer, re-read the question to ensure you’ve calculated exactly what was asked. This can be particularly important when answering questions under timed conditions during the actual CAT exam date.
9. Getting stuck in lengthy methods
Some problems can be solved through logic, options, or reverse calculation, but we end up doing full-blown algebra.
Avoidance tip: Always scan the options. See if plugging them in or using logical elimination is faster.
10. Overdependence on calculators during preparation
Relying too much on calculators while practicing will reduce your mental math speed.
Avoidance tip: Practice manual calculations and use the on-screen calculator only when absolutely necessary.
Final thoughts
Mastering CAT QA isn’t just about learning concepts—it’s about avoiding common traps that trip most aspirants. Identify which of these mistakes you’re prone to and work consciously to correct them during mocks and practice sessions. Make sure you’re familiar with the CAT exam pattern and stay updated on the CAT exam date so you can pace your preparation effectively. Also, don’t delay filling out the CAT application form—planning ahead helps you stay focused on what really matters: accuracy, strategy, and consistency.