We have seen what natural and whole numbers are.
The whole numbers comprise of the entire set
of natural numbers and zero.
So what are integers then? Let's zoom in a bit.
Along with whole numbers,
the set of integers also includes negative numbers
like minus 1, minus 2, minus 3 and so on.
We have numbers like 1, 2 ,3 and so on, so that we can count.
We also know why we have a 0. Now the question, why negative numbers?
The most basic example would be temperature.
The temperature can go below '0' degrees and the temperature
below '0' degree is negative. Like 'minus 10 degrees'.
Let us see a different example.
Suppose you gave your friend 100 rupees,
and that friend returned just 50 rupees.
What is the net amount you have now?
The net amount you have is 'minus 50 rupees'.
We know there is no note available in the market
which amounts to 'minus 50 rupees'.
But a negative sign tells us that you are in a loss.
Coming back to integers. All these numbers are integers.
We zoom out slightly to understand another interesting concept.
The numbers 1, 2, 3, 4, 5 and so on are called positive integers.
And numbers minus 1, minus 2, minus 3
and so on are called negative integers.
We can also define natural numbers,
as positive integers.
Then what about '0'? Well, it's neither positive nor negative.
Now look at all three of them together. It tells us that
all natural numbers and whole numbers are integers.
The set of integers, would look something like this.
And the set of integers are represented by the letter 'Z'.
Now we know what integers are and why they are used.
