Numbers

Numbers are used to express quantity. They also tell the order of things. Numbers are also used as labels.

Numbers are expressed by symbols. 1, 2, 3, 4 is a representation of numbers.

Quantity represented by numbers can be modified. When a quantity is modified its representation also changes. The modified quantity is represented by a different number. 

Quantity changes when some addition is made, or the quantity has been lessened. 

When addition is made, we can apply the arithmetic operator '+'. The method of using the operator is:

Previous Quantity + Current Amount = Modified Quantity

If

  Previous Quantity = 2

  Current Amount = 7

       then

               2 + 7 = 9 ( Modified Quantity )

In the above case the value of Modified Quantity will always be greater than Previous Quantity.

Similarly we can use the arithmetic operator '-'. 

Previous Quantity - Current Amount = Modified Quantity 

In the above case, the value of Modified Quantity will be less than Previous Quantity.

In Computer Science too numbers are used. Here numbers can be identified by alphabets. We can write,

a = 4

Here '4' is identified by 'a'. Now, suppose

a = 5

We can see that 'a' is now representing '5'. Previously it held '4'. So, truly 'a' has the ability to vary its values at different times. Yes, it is a variable representative of numbers. It is simply called variable. Firstly, it represented '4'. Now  it represents '5'.

Suppose,

c = 7

There is a rigid rule that once 'c' associates itself with a number, 'c' cannot  further have a different association. So, if it is wrong to do

c = 9

then surely 'c' is a representative  that is constantly representing '7'. 'c' is also called as simply constant. Any attempt to modify the number ( '7' ) is not approved by the representative  i.e., 'c'. 

Numbers help us to perform repetitively. Starting from a small number  we can begin a task. As a task is repeated, the number is incremented. At the end the final value of the number tells us about the number of repetitions.

Suppose,

c = 6

Let us suppose,

count = 0

Each time '4' us added to c, we increment the count by '1'.

So,

c = 6 + 4 

count = 0 + 1 = 1

Again 

c = 6 + 4 + 4

count = 1 + 1 = 2

Clearly, count = 2 tells that '4' has been added two times to c = 6.

So, we studied how numbers help to modify quantity. We also saw that numbers can have representatives. A variable representative can represent various numbers. We can have a representative that can represent only the same number all the time. Such representative is called as simply constant. Next,  it has been shown how here repetitions can be counted.