Prime Numbers 1 to 25

A prime number is a natural number with no positive factors other than 1 and the number itself. And the prime number can only be evenly divisible by 1 and the number itself. Here are some basic properties of prime numbers:

Every number greater than 1 is divisible by at least one prime number.

Two prime numbers are always relatively prime to each other.

Every even positive integer greater than 2 can be written as the sum of two prime numbers.

Every composite number can be uniquely factored into prime factors.

Except for 2, all prime numbers are odd; 2 is the only even prime number.

A prime number chart is a table showing the prime numbers in increasing order.

The chart simply includes all the prime numbers up to a certain limit for identifying the prime numbers within a range.

For kids, it will be less difficult to understand the prime numbers through the chart.

The significance of this prime number chart is used in different fields like the foundation of mathematics and the fundamental theorem of arithmetic.

The list of all prime numbers from 1 to 25 provides a comprehensive view of numbers in this range that can only be divided by 1 and the number itself.

The prime numbers in the range of 1 to 25 include 2, 3, 5, 7, 11, 13, 17, 19, and 23.

Prime numbers and odd numbers are the numbers that are only divisible by 1 and the number itself.

They cannot be evenly divisible by 2 or other numbers. 2 is the only even prime number, which divides all the non-prime numbers.

Therefore, except 2, all prime numbers are considered as the set of odd numbers.

Prime numbers are a set of natural numbers that can only be divided by 1 and the number itself. Here are the two important ways to find whether a number is prime or not.

By Divisibility Method:

To find whether a number is prime or not, we use the divisibility method to check. If a number is divisible by 2, 3, or 5 then it will result in a non-prime number. Prime numbers are only divisible by 1 and itself, so if a number is divisible by the number itself and 1, it is meant to be a prime number. For example: To check whether 17 is a prime number,

Step 1: 17 ÷ 2 = 8.5 (remainder ≠ 0)

Step 2: 17 ÷ 3 = 5.67 (remainder ≠ 0)

Step 3: 17 ÷ 5 = 3.4 (remainder ≠ 0) Since no divisors are found, 17 is a prime number.

By Prime Factorization Method:

The prime factorization method is the process of breaking down the composite number into the product of its prime factors. The method of prime factorization helps to identify the prime numbers up to 25 by building the smallest blocks of any given number. For example: The prime factorization of 24: Let's break it down into the smallest prime numbers until it can’t divide anymore.

Step 1: 24 ÷ 2 = 12

Step 2: Now, we divide 12, 12 ÷ 2 = 6

Step 3: Now take 6, divide the number with 2 6 ÷ 2 = 3

Step 4: Take 3. 3 ÷ 3 = 1 (since 3 is a prime number, and dividing by 3 gives 1) Therefore, the prime factorization of 24 is: 24 = 2³ × 3.

Rule 1: Divisibility Check:

Prime numbers are natural numbers that are greater than 1 and have no divisors other than 1 and the number itself. In the divisibility check rule, we check whether the prime number is divisible by 2, 3, and 5. If it's divisible by these numbers, then it's not a prime number.

Rule 2: Prime Factorization:

In this prime factorization method, we break down all the numbers into their prime factors, showing them as the product of prime numbers.

Rule 3: Sieve of Eratosthenes Method:

The method, Sieve of Eratosthenes is an ancient algorithm used to find all prime numbers up to a given limit. First, we list all the numbers from 1 to 25. Then start with the first prime number, 2. Mark all the multiples of 2 as non-prime. Repeat the process for the next unmarked prime number and continue until you reach the square root of 25, approximately 5. The remaining unmarked numbers are the prime numbers.

Tips and Tricks for Prime Numbers 1 to 25 

Use common shortcuts to memorize the prime numbers. 2, 3, 5, 7, 11, 13, 17, 19, 23 use these numbers as reference.

Practice using the method of Sieve of Eratosthenes efficiently.

Numbers like 4, 8, 9, 16, 25 are never meant to be prime.

Knowing the common powers of numbers helps in avoiding unnecessary checks.

• Prime numbers: Natural numbers greater than 1 that are divisible only by 1 and the number itself. For example: 2, 3, 5, 7, 11, 13, 17, 19, 23.

• Odd numbers: Numbers that are not divisible by 2. All prime numbers except 2 are odd. For example: 3, 5, 7, 11, 13, 17, 19, 23.

• Composite numbers: Non-prime numbers that have more than two factors. For example, 4 is a composite number because it is divisible by 1, 2, and 4.

• Sieve of Eratosthenes: An ancient algorithm used to find all prime numbers up to a given number by systematically marking the multiples of each prime starting from 2.

• Divisibility: The property of being divisible by a number without leaving a remainder. A prime number is not divisible by any number other than 1 and itself.