natural numbers

Natural Numbers

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What are Natural Numbers?

  • Natural numbers are the counting numbers starting from 1 and going up to infinity.
  • N = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, …}

Importance of Natural Numbers

Natural numbers are important because:

  • They are the first numbers we learn 😀
  • Used in daily life for counting
  • Form the base of arithmetic
  • Essential for higher mathematics

Without natural numbers, mathematics cannot begin.

Even and Odd Natural Numbers

Natural numbers are divided into:

Even Numbers

Numbers divisible by 2
Examples: 2, 4, 6, 8, 10…

Odd Numbers

Numbers not divisible by 2
Examples: 1, 3, 5, 7, 9…

Difference Between Natural and Whole Numbers

Natural NumbersWhole Numbers
Start from 1Start from 0
1, 2, 3, 4…0, 1, 2, 3

So, all natural numbers are whole numbers, but not all whole numbers are natural numbers.

Properties of Natural Numbers

Natural numbers follow some important properties:

1. Closure Property : A set of numbers is closed under an operation if performing that operation on numbers in the set gives a result that is also in the same set.

  • Addition Closure property : When we add two natural numbers, the result is always a natural number.
    Example: 5 + 3 = 8
  • Multiplication Closure property : When we multiply two natural numbers, the result is always natural.
    Example: 4 × 6 = 24
  • But subtraction is not always closed. Example: 3 − 5 = −2 (not a natural number)
  • Subtraction and Division may not result in a natural number.

2. Commutative Property : If changing the order of numbers does not change the result, the operation is commutative.

  • Commutative Property of Addition : Order of numbers does not change the sum : 4 + 7 = 7 + 4
  • Subtraction is not commutative
  • Commutative Property of Multiplication : Order of numbers does not change the product : 3 × 5 = 5 × 3

Order does not matter.

3. Associative Property

If changing the grouping of numbers does not change the result, the operation is associative. Grouping does not matter.

  • Associative Property of Addition : Grouping the numbers does not change the sum : (2 + 3) + 4 = 2 + (3 + 4)
  • Associative Property of Multiplication : Grouping the numbers does not change the product : (2 × 3) × 4 = 2 × (3 × 4)

Associative Property does not hold true for subtraction and division.

4. Distributive Property

  • Distributing Multiplication over Addition : a(b + c) = ab + ac
  • Distributing multiplication over subtraction : a(b – c) = ab – ac

5. Identity Property : An identity element is a number which, when used in an operation, does not change the original number. Number stays the same.

  • Additive identity: 0 (a + 0 = a)
  • Multiplicative identity: 1 (a × 1 = a)