Properties of Real Numbers

Top

Sub Topics Commutative Properties of Real Numbers Commutative Property of Addition Commutative Property of Multiplication Associative Property of Real Numbers Associative Property of Addition Associative Property of Multiplication Distribution Property of Real Numbers Density Property of Real Numbers Identity Property of Real Numbers Identity Property of Addition Identity Property of Multiplication

Real Numbers are used to measure the continuous values. A real number can be rational number or irrational number or it may be positive, negative or zero. It may also be algebraic or transcendental. Properties of Real Numbers that are used in various expressions and equations as follows: 1. The real numbers are dense in nature. Within two real numbers lies an infinite other real numbers. 2. The real numbers holds true for Commutative Property under addition and multiplication: a + b = b + a a * b = b * a 3. The real numbers holds true for Associative Property under addition and multiplication: a + ( b + c ) = ( a + b ) + c a * ( b * c ) = ( a * b ) * c 4. Distributive property holds true on real numbers: a * (b + c) = (a * b) + (a * c) a + (b * c) = (a + b) * (a + c) 5. The additive and multiplicative identity property for real number is: a + 0 = a a * 1 = a 6. Inverse property of real number is: a + (- a ) = 0 a * ($\frac{1}{a}$) = 1 7. Zero property of real number is: a * 0 = 0

Commutative property is an important part of mathematics, which is used to solve the problems of Algebra. In a proper definition, real numbers are those numbers that are not imaginary numbers. The Real Numbers did not have a name before Imaginary numbers, that‘s why they were known as a real numbers. Commutative properties holds true under two operations which are addition and multiplication.

1.Commutative property of addition:

a + b = b + a

In the above given equation, it shows the commutative property of real numbers by addition. The Commutative Property of addition states that altering the arrangement of two numbers that are added does not make any modification in the final result i.e, we can sum up numbers in any order but it does not affect the final result.. In the general sense, in any an additive equation you can change the arrangement of real numbers anywhere but final result does not get affected through this shift of numbers. Here are some examples through which we can easily describe the Commutative property of addition.

e.g, 4 + 5 = 5 + 4 = 9

2.Commutative property of multiplication:

a * b = b * a

In the above given equation, it shows the commutative property of real numbers by multiplication. The commutative property of multiplication states that altering the arrangement of two numbers that are added does not make any modification in the final result i.e, we can multiply numbers in any arrangement it wont affect the concluding result. In the general sense, in any an multiplicative equation you can change the arrangement of real numbers anywhere but final result does not get affected through this shift of numbers. Here are some examples through which we can easily describe the Commutative property of multiplication.

e.g, 4 * 5 = 5 * 4 = 20

Associative property is an important part of mathematics, which is used to solve the problems of Algebra. In a proper definition, real numbers are those numbers that are not imaginary numbers. The Real Numbers did not have a name before Imaginary numbers, that‘s why they were known as a real numbers. Associative properties holds true under two operations which are addition and multiplication.

1. Associative Property of Addition

a + (b + c) = (a +b) + c

In the above given equation, it shows the associative property of real numbers by addition. The Associative Property of Addition states that altering the arrangement of brackets between the operators does not make any modification in the final result i.e, we can sum up numbers in any order but it does not affect the final result. Here are some examples through which we can easily describe the Associative property of addition.

e.g, 3 + (4 + 5) = (3 + 4) + 5 = 12

2. Commutative Property of Multiplication

a * (b * c) = (a * b) * c

In the above given equation, it shows the associative property of real numbers by multiplication. The Associative Property of multiplication states that altering the arrangement of brackets between the operators does not make any modification in the final result i.e, we can multiply numbers in any arrangement it wont affect the concluding result. Here are some examples through which we can easily describe the Associative property of multiplication.

e.g, 3 * (4 * 5) = (3 * 4) * 5 = 60 The Associative property of addition states that altering the arrangement of brackets between the operators does not make any modification in the final result i.e, we can sum up Numbers in any order but it does not affect the final result.

The Associative Property of addition can be explained by some real life applications:

Example:
Ashley goes to a super market and buys a chocolate for Rs.10, a diary for Rs.15 and a pen for Rs.5. How much does she want to give to the cashier of the super market?

Mental calculation done by ashley:
15 + 5 = 20
10 + 20 = 30
i.e, 10 + (15 + 5) = 30

Calculation done by the cashier:
10 + 15 = 25
25 + 5 = 30
i.e, (10 + 15) + 5 = 30

We observe that in both the cases we get the same result.

This property of addition is called associative property of addition. According to the associative property of addition, the sum of any three given numbers remain same, even if we change the arrangement of brackets between the operators. So, a + (b + c) = (a + b) + c where a, b and c are any numbers. The distributive property can be explained by some examples:

1. 5 * (4 + 3) = (5 * 4) + (5 * 3) = 35
2. 2 * (3 + 6) = (2 * 3) + (2 * 6) = 18

Real numbers are used to measure the continuous values. A real number can be rational number or irrational number or it may be positive, negative or zero. It may also be algebraic or transcendental.

According to the density property, the Real Numbers are infinite. Between two real numbers lies an infinite other real numbers. For examples between 3 and 4 lies $\frac{3}{2}$, $\frac{3}{4}$, $\frac{3}{5}$, $\frac{3}{7}$, $\frac{3}{8}$, $\frac{3}{11}$,....... etc. This means that real numbers cannot be counted and there can exist uncountable number of real numbers in the number system.

To prove that the real numbers are dense:

1. Consider any two real numbers say $\frac{3}{4}$ and $\frac{3}{8}$.
2. Add them $\frac{3}{4}$ + $\frac{3}{8}$ = $\frac{9}{8}$
3. Divide it by 2 and it gives the mid-value of $\frac{3}{4}$ and $\frac{3}{8}$. So, $\frac{9}{16}$ lies between $\frac{3}{4}$ and $\frac{3}{8}$.
4. Similarly, we can find the mid-value of $\frac{3}{4}$ and $\frac{9}{16}$ and this will continue.

Hence it is proved that the real numbers are dense.

Real numbers are those numbers that are not imaginary numbers. The Real Numbers did not have a name before Imaginary numbers, that‘s why they were known as a real numbers. Identity properties holds true under two operations which are addition and multiplication.

1. Identity Property of Addition:

a + 0 = a

The above equation shows the Identity Property of Addition. The identity property of addition for real numbers states that, there exist a real number 0 such that if we add any real number to that number, the number remains unchanged.

e.g, 4 + 0 = 4

Here we observe that when 0 is added to a real number 4 the result remains unchanged, so we say that 0 is additive identity.

2. Identity Property of Multiplication:

a * 1 = a

The above equation shows the Identity Property of Multiplication. The identity property of multiplication for real numbers states that, there exist a real number 0 such that if we multiply any real number to that number, the number remains unchanged.

e.g, 4 * 1 = 4

Here we observe that when 0 is multiplied to a real number 4 the result remains unchanged, so we say that 0 is multiplicative identity. The Identity property of addition for real Numbers states that, there exist a real number 0 such that if we add any real number to that number, the number remains unchanged.


The identity property of addition can be explained by the following examples:

1. 4 + 0 = 4
2. 2.7 + 0 = 2.7
3. 11 + 0 = 11
4. $\frac{3}{4}$ + 0 = $\frac{3}{4}$

Another thing to be remembered is that when a real number is added to its additive inverse we obtain the additive identity. The Identity property of multiplication for real Numbers states that, there exist a real number 1 such that if we multiply any real number to that number, the number remains unchanged.


The identity property of multiplication can be explained by the following examples:

1. 4 * 1 = 4
2. 2.7 * 1 = 2.7
3. 11 * 1 = 11
4. $\frac{3}{4}$ * 1 = $\frac{3}{4}$

Another thing to be remembered is that when a real number is multiplied to its multiplicative inverse we obtain the multiplicative identity.