Showing posts with label Division. Show all posts
Showing posts with label Division. Show all posts

Fibonacci Sequence

The Fibonacci Series is 0,1,1,2,3,5,8,13,21,34,55,......



This Series is generated by adding two number before it :
for example :
5 is found by adding two numbers before it that is 2+3.
Similarly 8 is found by adding two numbers before it that is 5+3.
and so on..

The Fibonacci Sequence can be written as a rule such as
 Xn=Xn-1 + Xn-2
For example : Xn-1=21 and Xn-2=13 Therefore Xn becomes 34.

When we  make a square as shown below we get a Spiral shape :




Golden ratio : If we take two successive number Fibonacci number we get a known as Golden Ration which has the approximate value as  1.61803399....
Bigger the pair of Fibonacci Numbers, the closer the approximation.

The symbol for Golden ration is φ (phi).


Fibonacci in Nature: 

The Fibonacci appears in the smallest, to the largest objects in nature. It is a way for information to flow in a very efficient manner.
some of the images below shows the Fibonacci sequence in Nature


Fibonacci sequence in Cancer Cell Division




Fibonacci sequence in Galaxy

How to find whether a large number is divisible by 13 ?


How to find whether a large number is divisible by 13 ?



Lets take an example : Is 377 divisible by 13 ?



Here is trick


37  -  9(7)  =  37  -  63  =  -26


As -26 is divisible by 13  we can say that 377 is also divisible by 13...



Lets take another example  :  Is 2054 divisible by 13 ?



Therefore


205  -  9(4)  =   205   -  36  =  169


Again



16  - 9(9)  =  16  -  81  =  -65



As -65 is divisible by 13 ... The number 2059 is divisible by 13...



Note :  Multiply the unit's place with 9 as in both the above examples....


How to find whether a number is divisible by 11 ?

How to find whether a number is divisible by 11 ?







Lets take a simple example.. Does 11 divides 154 ?


Here is a trick...



Arrange 154 in the following manner



(1 + 4) - 5  =  5  -  5 =  0  Since 11 Divides 0  the number 154 is divisible by 11...



 Lets take second example.. Does 11 divides 2607 ?



Arrange the number in the following manner...



(2  +  0) - (6 + 7) = 2 - 13  =  -11


Since 11 divides -11  the number 2607 is divisible by 11...



Now lets take a  large number 3469917


Again arrange the number



(  3  +  6  +  9  +  7  )  -  (  4  +  9  +  1  )  =   ( 25 ) - ( 14 ) = 11  



Since 11 divides 11 the number 3469917 is divisible by 11....



Note : If 11 does not divides the result(11 in the above example) then your number is not divisible by 11..


How to find whether a number is divisible by 9 ?

How to find whether a number is divisible by 9 ?









Lets take a small example ... Is 243  divisible by 9 ?




Here is a trick 2 + 4 + 3 = 9  since 9 is divisible by 9 the number 243 is divisible by 9..



Lets take another example 281475..




So adding the numbers we get




2  +  8  + 1  +  4  + 7  +  5  =   27  as 27 is divisible by 9 the number 281475 is also divisible by 9...




Note : You can also add the result further... for e.g., the above result is 27 so 2  +  7  =  9  which is   divisible by 9

How to find whether a number is divisible by 6 ?


To check whether the number is divisible by 6 requires two step



Step 1 :  To check whether the number is divisible by 2.


Step 2 :  Sum up the digit and check whether it is divisible by 3.


For example : 138

Step 1 : 138 is divisible by 2 as 8 is divisible by 2....


Step 2 : 1  +  3  +  8  = 12  which is divisible by 3....

As the number satisfy both the steps the number is divisible by 6


Note : To know more about numbers divisible by 3 click here...


Lets take a bigger number 27402

Step 1 : 27402 is divisible by 2 as 2 is divisible by 2 in the unit's place...


Step 2 : 2  +  7  +  4  +  0  +  2  = 15  as 15 is divisible by 3...


As the number satisfy both the steps the number 27402 is divisible by 6...


Note  :  Even if one of the above step is missing then the number is not divisible by 6...

How to find whether a large number is divisible by 3 ?




Lets consider a small number 234 is divisible by 3.



So here is a trick     2 + 3 + 4 = 9 



Since 9 is divisible by 3 



Therefore 234 is divisible by 3....



Now consider a large number  27934576592477693217



So

2 + 7 + 9 + 3 + 4 + 5 + 7 + 6 + 5 + 9 + 2 + 4 + 7 + 7 + 6 + 9 + 3 + 2 + 1 + 7 = 105



You can further add 1 + 0 + 5 = 6



As 6 is divisible by 3



Therefore 27934576592477693217 is divisible by 3...

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