Last updated on June 30th, 2025
A square of a number is the multiplication of a number ‘N’ by itself two times. 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 21 to 30.
Numbers 21 to 30, when squared, give values ranging from 441 to 900. Squaring numbers can be useful for solving complex math problems. For example, squaring the number 25 implies multiplying the number twice. So that means 25 × 25 = 625. So let us look into the square numbers from 21 to 30.
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 21 to 30 given below. Understanding these values helps in various math concepts like measuring areas and so on. Let’s dive into the chart of squares.
We will be listing the squares of numbers from 21 to 30. 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 21 to 30. Square 21 to 30 — 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 21 to 30. Square 21 to 30 — 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 21 to 30. How to Calculate Squares From 21 to 30 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 22 as N. Multiply the number by itself: N² = 22 × 22 = 484 So, the square of 22 is 484. You can repeat the process for all numbers from 21 to 30. 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 29. 29² = (30 - 1)² To expand this, we use the algebraic identity (a - b)² = a² - 2ab + b². Here, a = 30 and b=1. = 30² - 2 × 30 × 1 + 1² 30² = 900; 2 × 30 × 1 = 60; 1² = 1 Now, adding them together: 900 - 60 + 1 = 841 So, the square of 29 is 841.
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, 24² = 24 × 24 = 576. 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 29, round it to 30 and adjust: 30² = 900, then subtract the correction factor 900 - (2 × 30 × 1) + 1² 900 - 60 + 1 = 841 Thus, 29² = 841.
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 21 to 30. 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 22 is 484 which is even. And the square of 23 is 529 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.
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.
Find the square of 28.
The square of 28 is 784. 28² = 28 × 28 = 784
We can break down 28 × 28 as: 28 × 28 = (30 - 2) × (30 - 2) To expand this, we use the algebraic identity (a - b)² = a² - 2ab + b². Here, a = 30 and b=2. = 30² - 2 × 30 × 2 + 2² 30² = 900; 2 × 30 × 2 = 120; 2² = 4 Now, adding them together: 900 - 120 + 4 = 784 So, the square of 28 is 784.
Find the square of 24.
The square of 24 is 576. 24² = 24 × 24 = 576
We can break down 24 × 24 as: 24 × 24 = (20 + 4) × (20 + 4) To expand this, we use the algebraic identity (a + b)² = a² + 2ab + b². Here, a = 20 and b = 4. = 20² + 2 × 20 × 4 + 4² = 400 + 160 + 16 = 576.
Find the square of 30.
The square of 30 is 900. 30² = 30 × 30 = 900
Since 30 × 30 is a simple multiplication, we directly get the answer: 30 × 30 = 900. Thus, the square of 30 is 900.
Observe the pattern in square numbers: 21², 22², 23²,… 30². Find the pattern in their differences.
The differences follow an odd-number sequence: 43, 45, 47, 49,… This shows that square numbers increase by consecutive odd numbers.
Calculating the squares: 441, 484, 529, 576, 625, 676, 729, 784, 841, 900 Now, finding the differences: 484 − 441 = 43, 529 − 484 = 45, 576 − 529 = 47, 625 − 576 = 49,…
Is 26 a perfect square?
26 is not a perfect square.
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: 5² = 25, 6² = 36 Since 26 is not equal to any square of a whole number, it is not a perfect square.
Odd square number: A square number that we get from squaring an odd number. For example, 23² is 529, which is an odd number. Even square number: A square number that we get from squaring an even number. For example, 24² is 576, which is an even number. Perfect square: The number which can be expressed as a product of a number when multiplied by itself. For example, 25 is a perfect square as 5 × 5 = 25. Multiplication method: A method to find the square of a number by multiplying the number by itself. For example, 21 × 21 = 441. Expansion method: A method that uses algebraic identities to simplify the squaring of larger numbers, such as using (a+b)² = a² + 2ab + b².
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.
: He loves to play the quiz with kids through algebra to make kids love it.