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
