factorial In math | Math tricks
What is factorial ?
Factorial is a very simple term and an interesting term to.
First of all let’s see the interesting sing of factorial …
“ ! “
Factorial is the multiplication of whole numbers from our chosen number down to 1 .
For example , suppose your chosen number is 5 . then what is the factorial of 5 ?
Yes that will be 5!
From definition, we can write it ,
5! = product of whole numbers from our chosen number down to 1 .
= 5 X 4 X 3 X 2 X 1. = 120
Like this ,
1) What will be the 6! ?
This will be = 6 X 5 X 4 X 3 X 2 X 1 =720
2) What will be the 10! ?
Ans : This will be 10! = 10 X 9 X 8 X 7 X 6 X 5 X 4 X 3 X 2 X 1.
Here is an interesting thing, we can write an factorial number using another factorial .
Such as , we know 4! = 4 X 3 X 2 X 1.
And 5! = 5 X 4 X 3 X 2 X 1.
See this two factorial number carefully . here in 5! and 4! the common term is ( 4 X 3 X 2 X 1 ) which is the factorial of 4.
So we can write 5! = 5 X 4! .
