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Square Numbers

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What is a Square Number?

According to the square number definition, they are the numbers that are multiplied by themselves. In other words, if a natural number is multiplied by itself, it is known as a square number. For example, 2 multiplied by itself (2x2) is a square number. When we multiply two equal integers by each other, the result of that ticket is basically a perfect square. Square numbers cannot be negative because if a negative number is multiplied by the same negative number it results in a positive number. Hence, square numbers are always positive.


Square numbers are named after a square because they form an area of a square. Imagine you have 9 items of 3 different categories. If we arrange it into a grid of 3 columns and 3 rows (3*3=9) placed vertically and horizontally, the grid will form a square.


Squaring Decimals

Just like squaring whole numbers (integers) is easy, it is also very easy to square decimals and both are done in the same way.


For example, 1.53 x 1.53 = 2.3409

                        7.19 x 7.19 = 51.6961


Properties of Square Number

  • Property 1- Square numbers will always end with the digits 0,1,4,5,6 and 9. For example 9,14,25,81,100 are perfect squares whereas numbers like 17,22,83 are not perfect numbers.


  • Property 2- A square number always contains an even number of zeros at the end and numbers containing an odd number of zeros cannot be square numbers. For example, 1600 3600  2500 square numbers whereas 1000, 250,160 are not square numbers.


  • Property 3- A number containing 1 or 9 as the last digit will always have 1 at the end of its square number. For example, the square number of 9 is 81 and 11 is 121.


  • Property 4- A number that has 4 or 6 as the last digit will have a square number ending with 6. For example, the square root of 4 is 16 and the square of 16 is 256.


  • Property 5- The square of an odd number is always odd and the square of an even number is always the reason. For example, the square of 15 is 125 and the square of 22 is 484.


  • Property 6- Square numbers a positive as two negative signs multiplied by each other result in a positive sign. For example -5×-5=25.


  • Property 7- Square root of a square number is a whole number. For example, the square root of 441 is 21 so your 441 is a square number. If the square of a number is a decimal of a fraction number then the number is not a perfect square. For example, √56=7.48, so your 56 is not a perfect square.


  • Property 8- For every natural number n, (n+1)²-n²=(n+1)+n.


  • Property 9- The sum of first n odd natural numbers is equal to the square of a number n.

1²=1

2²=1+3

3²=1+3+5

4²=1+3+5+7 and so on.


  • Property 10- For any natural number M greater than 1,

(2m,m²-1,m²+1) is a Pythagorean triplet.


Below  is the Table of Square Numbers From 1 to 100:

1²=1

21²=441

41²=1691

61²=3721

81²=6561

2²=4

22²=484

42²=1764

62²=3844

82²=6724

3²=9

23²=529

43²=1849

63²=3969

83³=6889

4²=16

24²=576

44²=1936

64²=4096

84²=7056

5²=25

25²=625

45²=2025

65²=4225

85²=7225

6²=36

26²=676

46²=2116

66²=4356

86²=7396

7²=49

27²=729

47²=2209

67²=4489

87²=7569

8²=64

28²=784

48²=2304

68²=4624

88²=7744

9²=81

29²=841

49²=2401

69²=4721

89²=7921

10²=100

30²=900

50²=2500

70²=4900

90²=8100

11²=121

31²=961

51²=2601

71²=5041

91²=8281

12²=144

32²=1024

52²=2704

72²=5184

92²=8464

13²=169

33²=1089

53²=2809

73²=5329

93²=8649

14²=196

34²=1156

54²=2916

74²=5476

94²=8836

15²=225

35²=1225

55²=3025

75²=5625

95²=9025

16²=256

36²=1296

56²=3136

76²=5776

96²=9216

17²=289

37²=1369

57²=3249

77²=5929

97²=9049

18²=324

38²=1444

58²=3364

78²=6024

98²=9604

19²=361

39²=1521

59²=3481

79²=6241

99²=9081

20²=400

40²=1600

60²=3600

80²=6400

100²=10000

FAQs on Square Numbers

1. What is the relation between square numbers and square root?

When a square root is multiplied, it produces a square number. Thus, a square root has an inverse operation than the square number. Let’s take an example, the square root of 36 is 6 because 6 x 6 = 36. So, we can say 36 is a square number and 6 is the square root of it. Finding the square root of a number can be much trickier than calculating the square number. Therefore, the modern calculator has the square root button to make the calculation easier.

2. How do we Square Negative Numbers?

We all know that when two negative or two positive numbers are multiplied to each other then the result will always be a positive number. For example, if we multiple -5 to -5 then the result will be 10. If 5 will be multiplied to 5, the result will be 10 as well. But what if a negative number is multiplied to a positive number or vice versa? The result would be a negative number. For example, if -3 is multiplied to 3, the result would be -9. A number cannot be a square number if it is a negative number because -3 and 3 are very different from each other. 

3. What is the symbol of a square number?

A square number can be denoted as n×n. For instance, the product derived by multiplying 2 is 4, so here, 4 is termed as a perfect square. Exponential notation is a square number donated as n² and is pronounced as "n" squared. For example 20×20=400, 21×21=441, 22×22=484.

4. How can you tell if a number is a perfect square?

There are a lot of ways to determine whether a number is a perfect square.  By using repeated division by prime factors we can find out whether a number is a perfect square or not. For example, to check whether 441 is a perfect square, you can start by factoring this number like 441=3×3×7×7. Here we can see that 3 and 7 are the numbers that exist twice. Make two sets 3×7×3×7 and multiply them 3×7=21 and 3×7=21. We get 21 twice that can also be written as 21². So we can conclude that 441 is a perfect square.

5. Who invented square numbers?

Around 1650 BC, the Egyptians used an inverse proportion method to calculate square roots. Somewhere around 200 BC, Chinese mathematical writings  demonstrate that the square numbers were  approximated by using the deficiency and excess method. Regiomontanus was the one who invented a symbol written as R for square roots.

6. What is the square root of 0?

The square root of 0 is equal to the square root of 0². It has only one square root and in fact, 0 is the only  real number. The square root of 0 is itself 0. A square number is the product of a number that gets multiplied by itself. If we multiply 0 twice by itself 0×0= then the answer will be 0, itself.