Shortcut tricks for Square Root upto infinity questions-Addition

Hello readers, here is a problem shortcut trick for a type of question which is mostly asked in many competitive exams like cat, mat, gate, ssc, ibps etc.
The type of questions are asked in many Competitive Exams. Through this trick, you will be able to solve that question in just 2 seconds.

These types of questions are very difficult to solve and might take 5-15 minutes to solve depending on the mental capability of the candidate. This type of questions has been asked several times in various exams as said above and most of the candidates are not able to solve them or if some of them are able to solve it, they would have spent a lot of time solving these questions.
What normally a candidate does to solve this types of questions is that the candidate will calculate the square root of 12 and will add up all the square root values so that he/she can reach to a nearest answer. But this process will take a big deal of time as this process is lengthy and will consume 5-15 minutes or more. But in competitive exams you don’t have that much sufficient and if you spend this much time in solving this type of question, you can also think that you can solve 5-10 other questions easily by leaving this type of question. But with this trick you will be able to solve this type of question in just 2 seconds.
So what I am discussing here is the shortcut trick to solve this types of question and this trick will solve this type of question in just 2 seconds.
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Here is an official video of this trick in which I have fully explained this trick.
Click on the link below to watch this video.
Here is also I am explaining this trick
So friends, if in this type of question, we imagine 12 as x. also x should be given even as 12 is even.
The answer will come when we equate x to n(n+1)   i.e.
in the above question, x is even and its value is 12. So think about those factors of 12 which make it equal to    n(n+1)
those factor can only be 3(3+1) means 3x4=12. the answer will be the bigger number means n+1
Means the answer will be n+1 means 4.

So it just takes 2 seconds to solve this question as you just have to think of the factors of the given number and you get the answer.

Here is the question that was asked in GATE 2013 and this types of questions are very important in competitive exams.
Decrease the first term from the last term
√81- √1= 9-1= 8 answer
This is the fastest trick for this type of questions among all types of trick. And you can solve them in just 2 seconds using this trick. If you don’t use this trick and apply other types of tricks, you will be wasting time in the exams.  And time is money.
So be fastest and learn the best trick only