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Last updated on June 30th, 2025

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Square 1 to 20

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A square of a number is the multiplication of a number ‘N’ by itself. Square numbers are used practically in situations like finding the area of a garden or measuring distance on maps. In this topic, we are going to learn about the square numbers from 1 to 20.

Square 1 to 20 for Indonesian Students
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Square 1 to 20

Numbers 1 to 20, when squared, give values ranging from 1 to 400. Squaring numbers can be useful for solving complex math problems. For example, squaring the number 5 implies multiplying the number by itself. So that means 5 × 5 = 25. So let us look into the square numbers from 1 to 20.

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Square Numbers 1 to 20 Chart

Learning square numbers helps us find the area of two-dimensional shapes like squares. Let’s take a look at the chart of square numbers 1 to 20 given below. Understanding these values helps in various math concepts like measuring areas and so on. Let’s dive into the chart of squares.

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List of All Squares 1 to 20

We will be listing the squares of numbers from 1 to 20. Squares are an interesting part of math that help us solve various problems easily. Let’s take a look at the complete list of squares from 1 to 20. Square 1 to 20 — Even Numbers Square numbers that are divisible by 2 are even. The square of any even number will result in an even number. Let’s look at the even numbers in the squares of 1 to 20. Square 1 to 20 — Odd Numbers When you multiply an odd number by itself, the result is also an odd number. When we square an odd number, the result will always be odd. Let’s look at the odd numbers in the squares of 1 to 20. How to Calculate Squares From 1 to 20 The square of a number is written as N², which means multiplying the number N by itself. We use the formula given below to find the square of any number: N² = N × N Let’s explore two methods to calculate squares: the multiplication method and the expansion method: Multiplication method: In this method, we multiply the given number by itself to find the square of the number. Take the given number, for example, let’s take 4 as N. Multiply the number by itself: N² = 4 × 4 = 16 So, the square of 4 is 16. You can repeat the process for all numbers from 1 to 20. Expansion method: In this method, we use algebraic formulas to break down the numbers for calculating easily. We use this method for larger numbers. Using the formula: (a+b)² = a² + 2ab + b² For example: Find the square of 14. 14² = (10 + 4)² To expand this, we use the algebraic identity (a + b)² = a² + 2ab + b². Here, a = 10 and b = 4. = 10² + 2 × 10 × 4 + 4² 10² = 100; 2 × 10 × 4 = 80; 4² = 16 Now, adding them together: 100 + 80 + 16 = 196 So, the square of 14 is 196.

Professor Greenline from BrightChamps

Rules for Calculating Squares 1 to 20

When learning how to calculate squares, there are a few rules that we need to follow. These rules will help guide you through the process of calculating squares. Rule 1: Multiplication Rule The basic rule of squaring a number is to multiply the number by itself. We use the formula given below to find the square of numbers: N² = N × N For example, 8² = 8 × 8 = 64. Rule 2: Addition of progressive squares In the addition of progressive squares, we calculate square numbers by adding consecutive odd numbers. For example, 1² = 1 → 1 (only the first odd number) 2² = 4 → 1 + 3 = 4 3² = 9 → 1 + 3 + 5 = 9 4² = 16 → 1 + 3 + 5 + 7 = 16 5² = 25 → 1 + 3 + 5 + 7 + 9 = 25. Rule 3: Estimation for large numbers For larger numbers, round them to the nearest simple number, then adjust the value. For example, to square 18, round it to 20 and adjust: 20² = 400, then subtract the correction factor 400 - (2 × 20 × 2) + 2² 400 - 80 + 4 = 324 Thus, 18² = 324.

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Tips and Tricks for Squares 1 to 20

To make learning squares easier for kids, here are a few tips and tricks that can help you quickly find the squares of numbers from 1 to 20. These tricks will help you understand squares easily. Square numbers follow a pattern in unit place Square numbers end with these numbers in the one digit 0, 1, 4, 5, 6, or 9. If the last digit of a number is 2, 3, 7, or 8, it cannot be a square number. For example, 25 is a square number that ends with 5, while 36 is also a square number that ends with 6. Even or Odd property The square of an even number will always be even, and the square of an odd number will always be odd. For example, the square of 2 is 4 which is even, and the square of 3 is 9 which is odd. Adding odd numbers Square numbers can be calculated by adding the odd numbers one after the other. For example, 1² = 1 → 1 (only the first odd number) 2² = 4 → 1 + 3 = 4 3² = 9 → 1 + 3 + 5 = 9 4² = 16 → 1 + 3 + 5 + 7 = 16 5² = 25 → 1 + 3 + 5 + 7 + 9 = 25.

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Common Mistakes and How to Avoid Them in Squares 1 to 20

When learning about squares, it’s natural to make some mistakes along the way. Let’s explore some common mistakes children often make and how you can avoid them. This will help get a better understanding of squares.

Mistake 1

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Confusing squaring as doubling

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Children think that squaring a number is the same as doubling it. For example, 5² is 25, not 10. Always remember that squaring means multiplying the number by itself.

Mistake 2

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Confusing square and square root

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Kids assume that squaring and square rooting are the same. For example, they might think that √9 equals 9², whereas they are not. Squaring increases the value, while the square root finds the original number.

Mistake 3

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Improperly squaring a negative number

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Kids assume that the square of a negative number is negative. For example, instead of writing (-6)² as 36, they write it as -36. Always remember that the square of a negative number is positive.

Mistake 4

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Assuming all composite numbers as perfect squares

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Kids assume that all composite numbers are perfect squares. For example, numbers like 18, 20, and 45 are composite but not perfect squares.

Mistake 5

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Using the wrong formula for squares

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Students sometimes apply incorrect formulas. For example, the formula for squares is N², meaning N × N, but they confuse it with 2N, which is multiplying the number N with 2, not squaring it. We must make sure we understand the difference and apply the correct formula.

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Square 1 to 20 Examples

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Problem 1

Find the square of 13.

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The square of 13 is 169. 13² = 13 × 13 = 169

Explanation

We can break down 13 × 13 as: 13 × 13 = (10 + 3) × (10 + 3) To expand this, we use the algebraic identity (a + b)² = a² + 2ab + b². Here, a = 10 and b = 3. = 10² + 2 × 10 × 3 + 3² 10² = 100; 2 × 10 × 3 = 60; 3² = 9 Now, adding them together: 100 + 60 + 9 = 169 So, the square of 13 is 169.

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Problem 2

Find the square of 19.

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The square of 19 is 361. 19² = 19 × 19 = 361

Explanation

We can break down 19 × 19 as: 19 × 19 = (20 - 1) × (20 - 1) To expand this, we use the algebraic identity (a - b)² = a² - 2ab + b². Here, a = 20 and b = 1. = 20² - 2 × 20 × 1 + 1² = 400 - 40 + 1 = 361.

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Problem 3

Find the square of 20.

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The square of 20 is 400. 20² = 20 × 20 = 400

Explanation

Since 20 × 20 is a simple multiplication, we directly get the answer: 20 × 20 = 400. Thus, the square of 20 is 400.

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Problem 4

Observe the pattern in square numbers: 1², 2², 3², … 10². Find the pattern in their differences.

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The differences follow an odd-number sequence: 3, 5, 7, 9, … This shows that square numbers increase by consecutive odd numbers.

Explanation

Calculating the squares: 1, 4, 9, 16, 25, 36, 49, 64, 81, 100 Now, finding the differences: 4 − 1 = 3, 9 − 4 = 5, 16 − 9 = 7, 25 − 16 = 9, …

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Problem 5

Is 15 a perfect square?

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15 is not a perfect square.

Explanation

Perfect squares are numbers that result from squaring whole numbers. If a number lies between two square values, it is not a perfect square. Find the closest squares: 3²=9, 4²=16 Since 15 is not equal to any square of a whole number, it is not a perfect square.

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FAQs on Squares 1 to 20

1.What are the odd perfect square numbers up to 20?

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2.Are all square numbers positive?

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3.What is the sum of the perfect squares up to the number 20?

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4.What is the square of 15?

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5.Are all prime numbers perfect squares?

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6.How does learning Algebra help students in Indonesia make better decisions in daily life?

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7.How can cultural or local activities in Indonesia support learning Algebra topics such as Square 1 to 20?

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8.How do technology and digital tools in Indonesia support learning Algebra and Square 1 to 20?

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9.Does learning Algebra support future career opportunities for students in Indonesia?

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Professor Greenline from BrightChamps

Important Glossaries for Squares 1 to 20

Odd square number: A square number obtained from squaring an odd number. For example, 3² is 9, which is an odd number. Even square number: A square number obtained from squaring an even number. For example, 4² is 16, which is an even number. Perfect square: A number that can be expressed as the product of a number multiplied by itself. For example, 9 is a perfect square as 3 × 3 = 9. Square: The result of multiplying a number by itself. For example, the square of 5 is 25. Squaring: The process of multiplying a number by itself. For example, squaring 6 results in 36.

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Jaskaran Singh Saluja

About the Author

Jaskaran Singh Saluja is a math wizard with nearly three years of experience as a math teacher. His expertise is in algebra, so he can make algebra classes interesting by turning tricky equations into simple puzzles.

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Fun Fact

: He loves to play the quiz with kids through algebra to make kids love it.

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