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