Quicker Maths

Shortcut to Find Square of a Number

Posted on June 21, 2010

Today I will discuss a very simple method of finding square of numbers between 26 to 74 mentally. In the subsequent post we will cover higher numbers. So keep watching this space to learn squaring any number within your mind

Square (also called perfect square) is an integer that is the square of an integer; in other words, it is the product of some integer with itself. So, for example, 9 is a square number, since it can be written as 3 × 3.

How to find the square of any number?

To apply this method you should know squares of 1 to 25 by heart. You can refer to this table to learn the same.

Number Square Number' Square'
1 1 13 169
2 4 14 196
3 9 15 225
4 16 16 256
5 25 17 289
6 36 18 324
7 49 19 361
8 64 20 400
9 81 21 441
10 100 22 484
11 121 23 529
12 144 24 576
* * 25 625

For finding square of any number between 26 to 75

Step 1. Find the difference between 50 and the number you want to square.

Scenario 1: If the number to be squared is greater than 50

Step 2. Add that many 100s to 2500 (which is the square of 50)

Step 3. Then add the square of the difference to the result of step 1

Scenario -2: If the number is less than 50

Step 2. Subtract that many 100s to 2500.

Step 3. Then add the square of the difference to the result of step 1

Example

Find out the Square of 67.

Step 1. Difference of 67 and 50 = 67-50 = 17
Step 2. This number is greater than 50. So add 1700 to 2500 = 4200
Step 3. Add square of 17 to step 2.

Answer = 4200+ 289 = 4489

Alternative method of calculating the square of a number:

Since, 67-50 = 17

67^2

We will be getting answer in 2 parts; see below – right hand side gives you tens and units digit. Left hand side gives you the remaining digits.

= 25 + 17 | (17)^2 ( | denotes separation )

= 42 | 289 (17^2 is 289. The 2 shown in subtext will be carried over and added to left hand side)

= 4489

You may also like:

  1. Trick to Find Square Root
  2. Trick to Find Square of Numbers from 51 to 59
  3. Vedic Multiplication of two numbers close to Hundred

Posted by Vineet Patawari

Comments (61) Trackbacks (1)
  1. nice method..very helpful :)

  2. 2^32=? Pls work out it in a simple method?

  3. To find the square of any number:

    square(25)= sq(2)sq(5)+20*2*5
    = 0425+200
    = 625

    square(115)= sq(11)sq(5)+20*11*5
    =12125+1100
    =13225

  4. For sqaure root:-
    (for all non perfect sqaures)
    Find two perfect squares that your square falls between. For example if I am trying to find the square root of 12, then I know my number is going to fall between the square root of 9 (3^2=9) and the square root of 16 (4^2=16).
    Divide your square by one of these two square roots. Therefore, I am going to divide my square, 12, by one of the square roots 3 or 4. I will choose 3. So, 12/3 = 4.
    I will average the result from Step 2 with the root I divided by. So, I take my answer from Step 2 (4), and will average this with the root I chose to divide my square by in Step 2 (3). Therefore, (4+3)/2 = 3.5. The square root of 12 is 3.5!
    try this with large numbers. for very small numbers like 2, 3 etc it doesn’t work i.e. as you try to find the square root of larger numbers you will get more precise answer……

    • I know one easiest way to find the square root.
      Ex: I want to find out the square of 76
      Explanation :
      a) 76 is nearer to 80 than 70
      b) square of 80 is 6400 we know that ( 8* 8 = 64*100= 6400)
      c)know multiply the 80 with twice difference of 80 and 76 (80-76 =4) (4*2 =8)
      d) 8*80 = 640
      e) subtract 640 from 6400 and add 6 (it is the last digit of 6 sqare) at ones digit. you got the answer

      Exception=
      1) if the number ends with 4 we need to add 16 or ends with 5 we need to add 25

    • find square root of 15 using ur formula..

  5. For sqaure root:-
    (for all non perfect sqaures)
    Find two perfect squares that your square falls between. For example if I am trying to find the square root of 12, then I know my number is going to fall between the square root of 9 (3^2=9) and the square root of 16 (4^2=16).

    Divide your square by one of these two square roots. Therefore, I am going to divide my square, 12, by one of the square roots 3 or 4. I will choose 3. So, 12/3 = 4.

    I will average the result from Step 2 with the root I divided by. So, I take my answer from Step 2 (4), and will average this with the root I chose to divide my square by in Step 2 (3). Therefore, (4+3)/2 = 3.5. The square root of 12 is 3.5!

    try this with large numbers. for very small numbers like 2, 3 etc it doesn’t work i.e. as you try to find the square root of larger numbers you will get more precise answer……

  6. sir,
    how can i find the square root of a number which is more than 4 digit( using short process)

  7. How to find the square root of a number like 2750.25??

  8. just square 5*5 and keep 25 a side and multiply 7*8 =56 then join them i.e 5625 answer

    its wery easy to find square of the two digit num ending with 5

    for example

    hey let me tel abt the suaring of two digit number ending with 5′s

    for ex take 25*25

    step 1: multiply 5*5=25
    step 2:multiply 2*3=6

    the answer is 625

    first of all wen u see 25*25 nd 35*35 etc wen ever u fing 2 digit numbers ending with 5 you just write 25 atlast and then multiply the first num with the conseqte num as shown above

    if it is 45*45
    u just write last 25
    and multiply 4*5=20
    so answer is 2025

  9. hi,thank u very much was very much helpfull.

  10. Is there any trick to find square of a 9 series number like 99, 999, 9999 and so on?

  11. Sir i request u.
    i m very confused in square form but i rember 1……..to ….30 sq.and qube form plz help me y any tricks find for any no. of squre….

  12. can anybody tell me how to find square of 25-50 and more than 100 from the same trick

  13. sir pls give the trick for find out the square of greater than hundred

  14. i want to know how to find the square of 136469

  15. hei i know many shortcuts .. i’ll help u catch me at karthikthebest007@gmail.com . iam very very interested and eager in maths . bye…….

  16. how to solve suare root of number greater than 75 ??

  17. how to find square root of number <75 ??

  18. HI !
    LEARN THE SQURE ROOT OF 1 TO 25

  19. HI,
    CUBE ROOT OF 512000
    STEP1 :- CLOSE THE LAST THREE NUMBERS AND THE REMAINND NUMBERS =512
    SEE THE IN WHICH NUMBER IS THERE IF IT IS IN BETWEEN THEN LEAST NUMBER CUBE
    STEP2 :- AND YOU SEE THE LAST NUMBER 0 IS 0 AND IF IT IS 4 THEN YOU SEE THE CUBE ROOT OF 4 IS 64 YOU SEE ONLY LAST NMBER

  20. There is another easy method….
    eg : 37 ^2
    Step I (Divided into three parts)

    Write as 3^2 | 2 * 3 *7|7^2

    Step II
    Leave on carry to the next part so that only one digit is left in 10th and unit’s place
    Then we get 13 | 7 |9

    • please explain Step 2 once again clearly sir!!!

    • Thanks Gokul for your suggestion. BTW the answer is 1369 and not 1379.
      Actually this is an application of the formula: (a+b)^2 = a^2 + 2*a*b + b^2; here a = 30 and b = 7.
      Arranging the same thing vertically will make it easier for you to understand –
      900
      420
      49
      ——-
      1369

      If written in the manner suggested by Gokula (vedic maths way), it becomes simpler.

  21. sir u all r doing a great job
    thanx Q so much 4 providing such a marvelous trick of finding a square….thank u so much sir…

  22. ya gud trick it works

  23. What is the best way to start planting a flower garden?

  24. if u wanna multiply 2digit number wid D another 2 digit number i hve 1 simple trick wic i wanna share wid U all
    e.g
    31 X 41
    den 1st a fall multiply 1st digit of one number wid D 1st digit of another number (like 3 X 4)
    u will get D first 2 digit of ur ans. i.e 12
    12 _ _
    den multiply 2nd digit of 1st number wid D 2nd digit of another number (like 1X 1)
    den u will get D last digit if ur ans i.e 1
    12_ 1
    know 1 middle digit is remaining
    4 this u hve 2 do RAINBOW multiplication
    means u hve 2 find D product of outside digit & den inside digit
    after this add the product of inside digit and outside digit [ 3 X 1(outside digit) + 4 X 1(inside digit) ]
    here u get D result 7
    1271 is D ans
    by this method u can easily find out D square also

  25. sir u all r doing a great job
    thanx Q so much 4 providing such a marvelous trick of finding a square

  26. Hi, afcourse this method is very helpfull for finding the squre and squre root

  27. 103*105=107,added the last term of 105 of value 5
    103+5=107

    104*104=108
    104+4=108
    thanx

  28. Thanks Nandeesh for suggesting further simplification. I am glad we have regular contributors like you.

  29. I think that for both the scenarios of whether number is less than 50 or more than 50, same method as scenario 2 will work.

    EX: 67

    67 – 25 | (17)^2 ( | denotes separation )

    = 42 | 289 (17^2 is 289. The 2 shown in subtext will be carried over and added to left hand side)

    = 4489

    EX: 37

    37 – 25 | (13)^2 ( | denotes separation )

    = 12 | 169 (13^2 is 169. The 1 shown in subtext will be carried over and added to left hand side)

    = 1369

  30. Hello Dear Nandeesh,

    The cases you have mentioned are very specific – I have discussed all of them in my earlier posts

    Squaring Number ending in 5 – http://www.quickermaths.com/squaring-number-ending-in-5/
    Multiplying 2 numbers, sum of whose units digit is 10 – http://www.quickermaths.com/vedic-multiplication/

    I will not say there aren’t simpler methods of finding square than the one mentioned in this post. But this method can be used for large variety of case.

    In any case, I appreciate your efforts of describing various methods. I will be happy to post any method suggested by you on QM (if it’s not already published on QM ). I must say your earlier posts were superb.

  31. With due respect to all, I feel, there are shorter methods for finding squares of numbers without need to remember squares of 1 to 25.

    Pl. go through the three tricks below:

    1. A quick way to square numbers that end in 5:
    75^2 = 5625

    75^2 means 75 x 75.
    The answer is in two parts: 56 and 25. The last part is always 25.
    The first part is the first number, 7, multiplied by the number “one more”, which is 8:
    so 7 x 8 = 56

    Similarly 852 = 7225 because 8 x 9 = 72.

    Before trying to square numbers which do not end in 5, please learn the following trick.

    2. Method for multiplying numbers where the first figures are the same and the last figures add up to 10.
    32 x 38 = 1216
    Both numbers here start with 3 and the last figures (2 and 8) add up to 10.
    So we just multiply 3 by 4 (the next number up) to get 12 for the first part of the answer.
    And we multiply the last figures: 2 x 8 = 16 to get the last part of the answer.

    And 81 x 89 = 7209
    We put 09 since we need two figures as in all the other examples.

    3. Method for squaring numbers that do not end in 5.

    Ex: 83 x 83 = 83 x (87 – 4) = 83 x 87 – 83 x 4

    As explained in trick 2 above, 83 x 87 = 7221.
    83 x 4 = 332.

    83 x 83 = 7221 – 332 = 6889

  32. @Nikhil: Ofcourse you can use the same method to find the square of numbers greater than 74. But in my next method I will give you the extension of this technique to find squares of number between 76 to 124 and so on.

  33. Hi , this method seems correct, but if I try to find square of say 89 then from your method i need to know (89-50)= 39^2. so in that case we may have to use to this method twice, at first to find 39^2 and then 89^2


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