Multipication on finger tips trick

Every time we see the sign of multiplication we start using the method we were taught in school.
It is time consuming but saves our brain fuel.
But if we use our brain then we can save time

What is Multiplication
Multiplication is addition.
Yes it is.

Consider this example
Multiply 2 by 3
2* 3 .

It means that add 2 three times or add 3 two times
2+2+2 = 6
   or
 3 + 3 = 6

So if we want to multiply 27 by 39 then it means addition of 27 to  39 time or addition of 39 to 27 term

there are diffrent ways of multiplication we can use depending upon our way of understanding

for e.g.

                           2  8
                         ×3  5 
                            140
                            84×
                            980
    
use this technique

28  is 20 +  8
35  is  30 + 5 

Now first multiply the exterior terms mean that 30 × 20 = 600
then multiply cross term                                     20 ×5 = 100
                                                                        30×8  =  240
in last                                                                8  ×5 =    40
 final result is addition                                      28×35=    980

Square of number starting with 5?

 In our daily life we use number 5 many times.In this method you will going to learn how to get square of number starting with 5 like 51, 52 53 etc and so on.

51*51=2601

RHS =  Square of number at ones place here it is  1*1=1 =>01

LHS =  25 + the number at ones place here its 1 =>(25 + 1)=26

answer is LHS/RHS = 26/01 =>2601

Now

52 * 52 = 2704

RHS =2 * 2 =04

LHS = 25 + 2=27

Answer is 27/04 = 2704

Now

54 * 54 = 2916

RHS = 4 * 4 = 16

LHS =25 + 4 = 29

Answer is 2916

Try to find square of 53 , 55, 56 ,57 etc

Square of number ending with 5?

The most easiest way to get square of number ending with 5.

It is based on Vedic maths.

By using this trick you can get square of any number ending with five within fraction of second

Consider a number

15*15 = . 225

Wondering how its works?

 Right hand side  it is always 25

LHS  = (number) * (number +1)

 here it is 1 * (1+1)= 2

so the answer is  2/25 (backslash is for indication only) so we get 225

next  number is 25

RHS =25

LHS= 2*(2+1)=>2*3=6

Answer is 625

Similarly

square of 35

3*(3+1)/25

1225

try the square of these number and share the result in Comments

45,55,65,75,85,95

Prime number Check Trick

 

Prime number check.

Prime numbers are those numbers which are only divisible by one and itself.

1,35,7,11,13,17 and so on……..

For small numbers it is easy to say whether number is Prime number or not.

But for large number like 1189 it is quite difficult to check its prime number test

But here is the trick that can check Prime number test within fraction of seconds.

If the number contains 2 or multiple of 2 at ones place it is not a prime number.

Like 2782, 1322, 1238, 9876 etc.

Whatever is the number use this trick.

Let the number be 89

Divide this number by 8 and then 9, 8+9=17 and 7+1=8

First step      = 89/8 not divisible

Second step = 89/9 not divisible

3^rd step          = 89/17 not divisible

Final step     =89/8 not divisible

So the number is Prime number.

Now check number 139

 Important Note   If number contains one at any position doesn’t check the number for one.

First step         =139/3 not divisible

Second Step   = 139/9 not divisible

Third step       = 139/13 not divisible

Final step        = 139/4 not divisible.

So the number is Prime number.

Now check the number 453

First step       = 453/4 not divisible

Second Step = 453/5 not divisible

Third step     = 453/3 = 151.

Since it is divisible so the number is not a Prime number.

This tricks works for a large number also. It will not take your much time to practice this trick.

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Trick to get square of two digit number?

How to square the double digit number

This trick use simple multiplication and addition to get square of two digit number with in fraction of second. You can use this method to double any number from 11 to 99.Here we go

Let us start with number 14

Square of 14= 14 ×14

  14

×14

 196

Right Hand side digit  =        4 * 4 = 16 ,So the first digit is 6 and one carry

Second digit  =   2(1×4) + 1 = 9

Third digit  =  1 ×1 = 1

So the answer is 196

General rule for multiplication

                               

                                               2^nd digit 2(1*4) + 1 carry from first digit

                                                            1        4             4 * 4 = 16

3rd digit  (1*1 + carry2^nd digit)             1         4     

                                                          1   9     6

now 23* 23

first digit 3*3 = 9
2nd digit = 2(2*3) + carry from first here it is 0 so  2nd digit = 12
3rd digit  = 2 * 2 + carry from second digit here it is 1 = 5
answer is                 529

Try  23 27 87  99 34 and share the result with others in comment