4- What are Numbers?

Till now we’ve learned about data analysis, you can read previous articles from here and watch previous videos from here

Know before proceeding to the next step, we need to take one step back, and talk about Numbers themselves,

The question here is what are numbers?

It seems like a very easy question, right? Yes, it’s easy, but will continue anyway

First thing you should know, numbers are mathematical objects, we use them to count, measure, and many other things, and as we’ve seen, most of the data analysis that we discussed till now is depending on numbers.

This subject is very long, that is why we will be talking today about the decimal numbers system only. Later on, we can talk about the rest of the types.

So what are decimals?

Simply. It means that the ones place value can carry ten numbers, from zero to nine

Then once it reaches nine, it will go back to zero, and the tens place value will be one, then to increase it you will increase the ones place value again, just as you’ve learned at school

Now, what are the categories of numbers?

The first thing to remember is the counting numbers, which are 1,2,3,4,5, etc.

These are numbers we use to count, you can’t count 1 and a half person, it should only be one, or two

Then, we have the whole numbers (W), which are Zero, plus counting numbers, the discovery of Zero changed a lot of aspects in mathematics, but let’s talk about that later

These two are called, Natural Numbers (N)

Then we have Integers (Z), which is the natural numbers plus negative numbers, like -1, -2, -3, etc

All previous categories are part of Real numbers (R)

Then we will talk about Fractions, and it’s numbers which can be written as a ratio between two numbers, like ? or ?, as you notice, it can also be written that way .5 or .75

These numbers are called Rational numbers (Q)

That implies the existence of Irrational Numbers

Irrational numbers are the numbers that you can’t write with decimals,

For example, is 1.4142135623730950488016887242097, and it continues to infinity, it cannot be written as decimal or fraction, it should be writing with a sign

Also like Pi πwhich is 3.14159265359, and it continues to infinity

As we said, all of these are Real numbers (R)

Again that implies the existence of numbers that are not real, which are the Imaginary numbers (I)

These numbers are not real like

We know that the root of a number, is asking, what number multiplied by itself, will give us the number under the root?

So when we say we are asking, what number multiplied by itself will give us four?

And the answer is easy, 2 or -2

But what is the number when we multiply by itself will give us -1?

Impossible, there is no real number can do that,

That’s why it’s called imaginary numbers

Then we have the Complex numbers (C) category

For example, it’s like it’s a combination of real and imaginary numbers

Now you know the basics of numbers, and it’s really important to know about, especially when you learn data analysis because with time you will find a different usage for each category of them, even imaginary numbers are used in electricity and advanced calculus.

That’s it for now, and if you have any question please leave it a comment and I will try to answer ASAP

Thank you!