Wednesday, 16 March 2016

[Q] Fast Calculation Tricks

There are some fast calculation hacks that can come in handy. Let's see them one by one -


1. Squaring a number with lightning fast speed

       Well you might have come across various tricks to find the square of a number, but I can bet you that my trick is the simplest and the fastest :)
Firstly memorize squares of numbers upto 25. I think many of you might be knowing it already, but for those who don't, please mug it. Now this trick will help you in squaring numbers upto 125 and trust me, for SSC you need this much only.

(a) For numbers close to 50

      (i) Numbers less than 50


        (ii) Numbers greater than 50
                  The process is almost same -  Compute (N - 50)
                  Add this difference to 25
                  E.g. 56*56=
                   1. 56 - 50 = 6
                   2. Last two digits = 6 * 6 = 36
                   3. First two digits = 25 + 6 = 31
                 Therefore, 56 * 56 = 3136

(b) Numbers close to 100

     (i) Numbers less than 100
      (ii) Numbers greater than 100
              The process is almost same -  Compute (N - 100)
              Add this difference to N
              E.g. 107*107=
              1. 107 - 100 = 7
              2. Last two digits = 7 * 7 = 49
              3. First three digits = 107 + 7 = 114
          Therefore, 107 * 107 = 11449

2. Squaring a number containing only '1'. E.g. 111, 1111, 1111111, etc.        Just count the number of ones. Like in 1111, there are 4 ones. So the square of 1111 is 1234321 (go from 1 to 4 and then back). Similarly, the square of 111111 = 12345654321

3. Finding product of two numbers of the form ab and ac, such that b+c=10. E.g. product of 43 and 47Last two digits = 3*7 = 21
First two digits = 4*(4+1) = 20
Hence 43*47 = 2021

4. Finding product of two numbers close to 100
(a) 103*109
Last two digits = 3*9 = 27
First three digits = (103 + 9) or (109 + 3) = 112
So 103*109 = 11227
(b) 92*97
Last two digits = 8*3 = 24  [100 - 92 = 8 and 100 - 97 = 3]
First two digits = (92 - 3) or (97 - 8) = 89
Hence 92*97 = 8924

Bonus Hack :

A very common question if SSC - 

I will tell you a formula that no 'paramount' will tell you :P
Note : Always take the difference between numerator and denominator as positive.
Answer : 3/(4-3) * 20 = 60 minutes

Next question - 
Rakesh runs at 5/4 of his usual speed and reaches the playground 5 minutes earlier. What is his usual time?

Answer : 5/(5-4) * 5 = 25 minutes



To buy the super-hit SSC Hack-Book, follow the below link-

Buy SSC Hack-Book

43 comments:

  1. If I ever become a superhero, you would be my sidekick for you know calculating the number of people I punch and stuff

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    Replies
    1. Hahaha...all your comments are creative :D

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    2. Thank u sir😊😊

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  2. Thankyou sir amazing tricks. A boon to those who can't do coaching

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  3. Thanku so much sir... solved many questions by your tricks.. thanks a lot..

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  4. Can u please tell me best test papers for practice apart from previous year questions?

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    Replies
    1. I think the previous year papers from 2010 to 2015 are more than enough.

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  5. Sir please give tricks over simple interest and compound interest...

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  6. Thanks sir. Very much useful. Waiting for mensuration hack. Hope it will come soon

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  7. sir please give provide tricks for geometry and mensuration

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  8. Great work sir, high quality content.
    You are doing a great help to aspirant like us.

    Thanks a lot

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  9. Great work sir, high quality content.
    You are doing a great help to aspirant like us.

    Thanks a lot

    ReplyDelete
  10. This comment has been removed by the author.

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  11. Awesome sir, 1.5 months for cgl-16 and i am following this blog closely. Please keep updating! Share all your strategies and tricks. Referring it to all my friends now. Superb.

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  12. Sir this is really helpful.Is it possible for you to guide on English. I am very bad at it. poor grammar and word power.

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  13. sir please give some information/ update/trick on english.

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  14. Great work very very useful.. hats off

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  15. My badluck.
    After all this time now i have known this blog.

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  16. A great help sir....can you please help out for preparation strategy for general awareness and all the sources that I need to prepare it within this month....Thank you..

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  17. Very very helpful to those who can't join coachings
    Thank u very much sir

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  18. Very very helpful to those who can't join coachings
    Thank u very much sir

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  19. Hello Sir, just now I have got to know about your blog. by studying thoroughly, I have become more pollyanna to clear SSC.
    I am dreaming about working in MEA. My short term goal was to clear SSC and enter MEA first as an assistant then I am aiming to be an IFS officer. (hopefully my zeal will turn me into a suave to be get eligible for that post). But unfortunately SSC just declared the vacancies' list and this year there is no vacancy in MEA. Disappointed........Sir, I wish to have a career guidance from your side. That would be highly appreciated.

    thank you
    Regards
    Ritesh Soni
    "emailriteshsoni@gmail.com"

    ReplyDelete
    Replies
    1. please read my recent post regarding reduction in the number of vacancies. I am hopeful that MEA will publish some vacancies. Although I cant say that for sure...

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  20. indeed ! a great assistance to the aspirants . thank you sir...

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  21. Thanks for such a useful tips.

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  22. Product of number near 100 is wrong sir...below hundred their is differnce between product and result

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  23. Product of number near 100 is wrong sir...below hundred their is differnce between product and result

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  24. Product of number near 100 is wrong sir...below hundred their is differnce between product and result

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  25. sir how to solve this ques using hacks....
    if x+1/x=5 then the value of (x^4+1/x^2)/x^2-3x+1

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  26. thank u sir for helping us with this easy tricks.

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  27. Sir please me fast trick of calculating number like 3.3^4 etc

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  28. please post something to calculate square roots of such nos. at a lightning speed

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  29. Sir pls tell me auctual cut off marks for engineering student to attend ssc cgl ? (Out of 10 ?)

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  30. Plz advised in English for Dec tier2

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  31. I want to buy book but it not succeed ..what to do??

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  32. How to claculate 3.3^4 in ur method, sir..y I'm asking this is, in the above article u have calculated for 47 which is too close to 50..In ur Hack book u have solved a question using decimal squares but I couldn't find a fastest way to solve squares of decimals in this article.... pls guide me Sir.. waiting for ur reply..thanks in advance..

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  33. How to claculate 3.3^4 in ur method, but I couldn't find a fastest way to solve squares of decimals in this article.... pls guide me Sir.. waiting for ur reply

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  34. How to claculate 3.3^4 in ur method, but I couldn't find a fastest way to solve squares of decimals in this article.... pls guide me Sir.. waiting for ur reply

    ReplyDelete