Number System সংখ্যা প্ৰণালী Part - 1 Mathematics (গণিত)

Number System | সংখ্যা প্ৰণালী | Part - 1 | Mathematics (গণিত) | CTET-2020 (Paper 1)

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Number System:- সংখ্যা প্ৰণালী

The number system is simply a system to represent or express numbers.

Numbers are expressed by means of figures –

  1, 2, 3, 4, 5, 6, 7, 8, 9 and 0 ---- called digits.
Natural Numbers: স্বাভাৱিক সংখ্যা

Numbers which we use for counting the objects are known as natural numbers.

It is also called as - Positive integers or Counting numbers.

Natural Numbers are denoted by ‘N’

  N = {1, 2, 3, 4,…….}
Whole Numbers: পূৰ্ণ সংখ্যা

When we include ‘zero’ in the natural numbers, it is known as whole numbers.

They are denoted by ‘W’.

  W= {0, 1, 2, 3, 4, 5,………}
Integers: অখণ্ড সংখ্যা

Integers include positive whole numbers, negative whole numbers, and zero.

The set of integers is like:-

  Integers = {… -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, …}
Even Number: যুগ্ম সংখ্যা

 The number which is divisible by 2 is known as an even number.  e.g. 2, 4, 8, 12, 24, 28 ..

 Numbers that end with a 0, 2, 4, 6 or 8 are called even numbers  e.g. 14, 202, 500, 8146, 99718.
Odd Number: অযুগ্ম সংখ্যা

The number which is not divisible by 2 is known as an odd number.

which means there is some remainder left after division

  e.g. 1, 3, 9, 11, 17, 19. .....
Prime Number: মৌলিক সংখ্যা

A prime number is a natural number greater than 1 Which have only two factors.

A prime number is a whole number greater than 1 whose only factors are 1 and itself.

  e.g. 2, 3, 5, 7, 11, 13. . ....

  (2 is the smallest prime number)
Composite Numbers: যৌগিক সংখ্যা

The number which is divisible not only by 1 or themselves but some other numbers also, are called Composite number.

In other words, the numbers which have more than two factors are called “Composite numbers”.

A number, other than 1, which is not a prime number is called a Composite Numbers

e.g. 4, 6, 8, 9, 12, 14 ...... and so on   

  (The number 1 is neither prime nor composite.)

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