Data Interpretation: Importance of Quick Mental Calculations

Importance of Quick Mental Calculations in DI

Importance of Quick Mental Calculations in DI

Last Updated on Nov 11, 2020

Data Interpretation being one of the most important format of the competitive exams, required a lot of data to be solved in less time which means you need to interpret a lot of data fast and in the most appropriate way to come to the right answer. The good part about data interpretation question is that it comes under a group question.

What group question means is, there is a huge data given in the form of a table, pie-chart, bar graphs or line graphs and then it is followed by 4-5 questions. So, the good thing is that is you interpret the data correctly, then there are high chances for you to solve the following questions correctly. On the other hand, if you don’t interpret the data correctly, then there are high chances that you will have a wrong answers for the questions that follow.

So, now the questions that come in our minds are:

  • How to speed up our speed to solve the data interpretation questions?
  • Are there any tricks to solve data interpretation questions?
  • How to solve data interpretation questions quickly and with correct answers?

Well, after a lot of work and research, many people have come to some conclusions. Let’s try to understand what it takes to be solve data interpretation questions fast and also to get the correct answers for the same.

Learn To Approximate (in Calculations): This might not be the thumb rule or the first rule, but it is an important point to begin with. DI questions require a lot of calculations, mostly in the form of averages, fractions, percentage, mean etc. You need to learn how to approximate the values, as most of the time, the result that we are looking at or the calculation that we are doing comes in decimals.

Example: 3458/234. The correct answer to this is 14.777777……8. Look at the result after dividing 3458 by 234. Now, if you are good in calculation (divide in this case), you will come to a conclusion that the answer will be 14.77777….8. After one or two decimal place you will chop off the rest and round it off. So, in this case it becomes 14.7777 or 14.78 or 14.8. But if you are too good in calculation or your speed is not that good, then you need to approximate.

  • Step 1: In this example, the numerator which is 3458 can be treated as 3460 which is the nearest integer for easy calculation.
  • Step 2: Denominator 234 can be treated as 235, again being the closest.

If you divide 3460 by 235, the answer is 14.723404255319148936170212765957. As can be seen, this is almost the same when 3458 is divided by 234. This is how you need to learn approximation.

Learn to Calculate Fast: More or less, this is the most important point or the most important rule while solving any type of question, be it a straight maths question or a puzzled one. If you can solve quickly, then there are no shortcuts, tricks or techniques that you need to know. The only thing that is required for you is to have an eye for the detail.

Learn to Analyze the Data Carefully: Sometimes, all you need to do is to see the data and answer the question. This does not involve any hard calculation, the calculation is simple but the data is too much and that is scattered all throughout the question. This mainly needs to be taken care when we are solving a DI question which has tables or where the data is given in tabular format with multiple rows and column.

We tend, to read the wrong data most of the time. You need to read the question and only see the data for the row which is asked in the question. Most of the time, we start analyzing the whole table, where it is not important at all. You will not be able to make any sense by just looking at the tables. Read the questions one by one and then analyze the respective data.

Lear Not to Assume Anything: Most of us assume a lot of things without getting to know about the fact and details in our daily lives. This is the human nature, and you can’t get rid off it while you are solving questions. You need to understand something: Firstly, if there is something missing or not given, it will have a reason for that. Most of the time, we tend to loose track and waste time, thinking why the certain data is not given or why the certain data is given in the way it is. Secondly, The values that are given are not by any chance or co-incidence. There is again a reason why the values are given like that.

The most common example for this is the use of the value of a pie: There are places when it is written to use it as 22/7. On the other hand, it is given to be used as 3.14. Just stay focused and do not assume anything use and do what is asked of you.

Learn to Avoid Unnecessary Calculation: This is derived from above points. You need to be careful while calculating the value of the given thing in a given question. What this means is: When you start your calculation for a given question, make it fast. You need to have fast calculation, which will help you make a decision of whether you should avoid a question or not.

Secondly, if there is a calculation for which there is an endless answer like if you divide 3460 by 235, the answer is 14.723404255319148936170212765957. This needs to be avoided completely. You are not required to solve anything beyond 2 decimal places, until and unless its been specifically asked in the question.

Do not Attempt DI questions in the last 10-15 mins: DI questions require time, eye for detail and quick calculation. Based on this, when you try to attempt these questions in the end, you tend to skip a lot of valuable information, we tend to skim through the data and end up getting wrong answers for the same. As, mentioned above, once you interpret the wrong data, you end up having wrong answers for all the questions that follow.

Learn to Pay Close Attention to Units: This is applicable not only for all the DI questions that you attempt but this is also important while solving questions on quantitative aptitude also. Most of the time, the mistake that we end up is not taking care of the unit.

Example: If there is a question that where the distance, and time is given and you are asked to find the speed. Make sure that everything is in the proper format. If you are supposed to calculate the speed in km/hr, then make sure that the distance is given in kms or else convert it into kms. Similarly, make sure the time is in hours, if not then convert it into hours. The other way round is to get the speed in m/s and then convert it into km/hr. But again, you need to take care and pay close attention to the units.

Practice as much as possible: This is the main and the thumb rule of everything. You need to practice as much as possible. There is no substitute or short cut for this. You don’t need anything else if you are regular in solving you problems, practicing them everyday. This gets you into momentum, it not only increases your calculation speed, but also makes sure that you have covered all the above points.

As, there is a way to approach to solve a puzzle, there is always a way to solve the questions in DI. Practice gives you eye for detail, it gives you an understanding to approximate, it gives you an experience to leave what is not necessary, or which involves heavy calculation and above all, it gives you confidence and great marks.


In this blog post, we have explained how to speed up your calculations in Data Interpretation . We have taken some examples for your easy understanding.
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