Prime Number

What is prime number?

A number which is divisible by only itself and 1 is a prime number. So, prime number has only two different factors normally 1 and the number itself.

A whole number having only 2 factors is called the prime number.

The two factors of a prime number are 1 and the number itself.

Let us find all the factors of 2, 3, 5, 7, 11, 13, 17 and 19.

(i) 2 → the factors are 1 and 2.

1 × 2 = 2

2 × 1 = 2

(ii) 3 → the factors are 1 and 3.

1 × 3 = 3

3 × 1 = 3


(iii) 5 → the factors are 1 and 5.

1 × 5 = 5

5 × 1 = 5


(iv) 7 → the factors are 1 and 7.

1 × 7 = 7

7 × 1 = 7


(v) 11 → the factors are 1 and 11.

1 × 11 = 11

11 × 1 = 11


(vi) 13 → the factors are 1 and 13.

1 × 13 = 13

13 × 1 = 13


(v) 17 → the factors are 1 and 17.

1 × 17 = 17

17 × 1 = 17


(vi) 19 → the factors are 1 and 19.

1 × 19 = 19

19 × 1 = 19


Therefore,

2 is divisible only by 1 and 2. Therefore, the factors of 2 are 1 and 2.

3 is divisible only by 1 and 3. Therefore, the factors of 3 are 1 and 3.

5 is divisible only by 1 and 5. Therefore, the factors of 5 are 1 and 5.

7 is divisible only by 1 and 7. Therefore, the factors of 7 are 1 and 7.

11 is divisible only by 1 and 11. Therefore, the factors of 11 are 1 and 11.

13 is divisible only by 1 and 13. Therefore, the factors of 13 are 1 and 13.

17 is divisible only by 1 and 17. Therefore, the factors of 17 are 1 and 17.

19 is divisible only by 1 and 19. Therefore, the factors of 19 are 1 and 19.


Thus 2, 3, 5, 7, 11, 13, 17 and 19 are prime numbers.

Prime Number

Note:

(i) All prime numbers except 2, are always odd numbers.

(ii) The number 2 is a prime as well as an even number.

(iii) All prime numbers are exactly divisible by 1 and the number itself.





4th Grade Math Activities

From Prime Number to HOME PAGE




Didn't find what you were looking for? Or want to know more information about Math Only Math. Use this Google Search to find what you need.



New! Comments

Have your say about what you just read! Leave me a comment in the box below. Ask a Question or Answer a Question.




Share this page: What’s this?

Recent Articles

  1. What is Area in Maths? | Units to find Area | Conversion Table of Area

    Jul 17, 25 01:06 AM

    Concept of Area
    The amount of surface that a plane figure covers is called its area. It’s unit is square centimeters or square meters etc. A rectangle, a square, a triangle and a circle are all examples of closed pla…

    Read More

  2. Worksheet on Perimeter | Perimeter of Squares and Rectangle | Answers

    Jul 17, 25 12:40 AM

    Most and Least Perimeter
    Practice the questions given in the worksheet on perimeter. The questions are based on finding the perimeter of the triangle, perimeter of the square, perimeter of rectangle and word problems. I. Find…

    Read More

  3. Formation of Square and Rectangle | Construction of Square & Rectangle

    Jul 16, 25 11:46 PM

    Construction of a Square
    In formation of square and rectangle we will learn how to construct square and rectangle. Construction of a Square: We follow the method given below. Step I: We draw a line segment AB of the required…

    Read More

  4. Perimeter of a Figure | Perimeter of a Simple Closed Figure | Examples

    Jul 16, 25 02:33 AM

    Perimeter of a Figure
    Perimeter of a figure is explained here. Perimeter is the total length of the boundary of a closed figure. The perimeter of a simple closed figure is the sum of the measures of line-segments which hav…

    Read More

  5. Formation of Numbers | Smallest and Greatest Number| Number Formation

    Jul 15, 25 11:46 AM

    In formation of numbers we will learn the numbers having different numbers of digits. We know that: (i) Greatest number of one digit = 9,

    Read More