# Why do we use numbers?

• Last Updated : 01 Nov, 2021

Numerals are the mathematical figures used in financial, professional as well as a social field in the social world. The digits and place value in the number and the base of the number system determine the value of a number. Numbers are used in various mathematical operations as summation, subtraction, multiplication, division, percentage, etc which are used in our daily businesses and trading activities.

Numbers are the mathematical figures or values applicable for counting, measuring, and other arithmetic calculations. Some examples of numbers are integers, whole numbers, natural numbers, rational and irrational numbers, etc.

The number system is a standardized method of expressing numbers into different forms being figures as well as words. It includes different types of numbers for example prime numbers, odd numbers, even numbers, rational numbers, whole numbers, etc. These numbers can be expressed in the form on the basis of the number system used.

The number system includes different types of numbers for example prime numbers, odd numbers, even numbers, rational numbers, whole numbers, etc. These numbers can be expressed in the form of figures as well as words accordingly.

For example, the numbers like 40 and 65 expressed in the form of figures can also be written as forty and sixty-five.

The elementary system to express numbers is called a number system. It is the standardized method for the representation of numerals in which numbers are represented in arithmetic and algebraic structure.

### Types Of Numbers

There are different types of numbers categorized into sets by the number system. The types are described below:

• Natural numbers: Natural numbers counts from 1 to infinity. They are the positive counting numbers that are represented by ‘N’. It is the numbers we generally use for counting. The set of natural numbers can be represented as N = {1,2,3,4,5,6,7,……………}
• Whole numbers: Whole numbers count from zero to infinity. Whole numbers do not include fractions or decimals. The set of whole numbers is represented by ‘W’. The set can be represented as W={0,1,2,3,4,5,………………}
• Rational numbers: Rational numbers are the numbers that can be expressed as the ratio of two integers. It includes all the integers and can be expressed in terms of fractions or decimals and is represented by ‘Q’.
• Irrational numbers: Irrational numbers are numbers that cannot be expressed in fractions or ratios of integers. It can be written in decimals and have endless non-repeating digits after the decimal point. They are represented by ‘P’.
• Integers: Integers are the set of numbers including all the positive counting numbers, zero as well as all negative counting numbers which count from negative infinity to positive infinity. The set doesn’t include fractions and decimals. The set of integers is represented by ‘Z’. Example: Z={………..,-5.-4,-3,-2,-1,0,1,2,3,4,5,………….}
• Decimal numbers: Any numeral value that consists of a decimal point is a decimal number. It can be expressed as 2.5,0.567, etc.
• Real number: The set of numbers that do not include any imaginary value and are constituent of all the positive integers, negative integers, fractions, and decimal values are real numbers. It is generally denoted by ‘R’.
• Complex numbers: They are a set of numbers that include imaginary numbers are complex numbers. It can be expressed as a+bi where “a” and “b” are real numbers. It is denoted by ‘C’.

### Why do we use numbers?

We use numbers in date, time, year and weather. We also use numbers in our daily life like school and work, counting money, measurements, phone numbers, password on our phone , locks, reading, page numbers, and TV channels.

Engineers use number according top specify fields like calculation to construct building and roads and Doctors use it for their patient blood counts and medicines.

1. Some one has to Call a member of a family or a friend using mobile phone.
3. The work which involves the idea of proportion and percentage.
4. In shopping like Weighing fruits, vegetables, meat, chicken, and others in market.
5. Using numbers of elevators to go places or floors in the building.
6. Look at the price of discounted items in a shopping mall.
7. Change the number of channels of your favorite TV shows.
8. The time you spent on work or school.

The number system includes different types of numbers for example prime numbers, odd numbers, even numbers, rational numbers, whole numbers, etc. These numbers can be expressed in the form of figures as well as words accordingly.

For example, the numbers like 40 and 65 expressed in the form of figures can also be written as forty and sixty-five.

The elementary system to express numbers is called a number system. It is the standardized method for the representation of numerals in which numbers are represented in arithmetic and algebraic structure.

### Sample Questions

Question 1: Add two smallest natural numbers?

Solution:

1, 2 are the smallest natural numbers

So 1 + 2 = 3 also a natural number

Question 2: When 7 times a number is increased by 5, the result is 40. Find the number.

Solution:

Lets assume the number is x

According to question

7 x + 5 = 40

Now we can write as

7 x = 40 – 5

and                      7x = 35

x = 35/7

x  = 5

So the number is 5.

Question 3: Find the value of a in the given equation 4a – 50 = 6.

Solution:

According to the equation,

=> 4a – 50 = 6

=> 4a = 50 + 6

=> 4a = 56

=>   a = 56/4

=>   a =  16

Therefore, the value of a is 16.

Question 4: Find the sum of 100 and 40 and then subtract 30 from the sum?

Solution:

Here, the sum of 100 and 40 by using the addition operation.

Sum = 100 + 40 = 140

Now, as per the question, subtract 20 from the sum,

140 – 30 = 110

Therefore, 110 is the final answer

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