Between the two terminal digits of the number, insert the sum of first and second digits, then sum of second and third digits.

Example:

614*11= 6...(6+1)..(1+4)..4 = 6754

Multiplication Of 2 Two-digit Numbers Where The First Digit Of Both The Numbers Are The Same And The Sum Of The Last Digit Of The Two Numbers Is 10

Let’s explain this rule by taking an example of 57*53. Here the first digit of both number is 5 and the sum of last digit of both numbers, that is, sum of 7 and 3 is 10. Hence, both conditions are met.

Now let us see how to calculate 57*53 using this technique:

Multiply 5 by 5+1. So, 5*6 = 30. Write down 30

Multiply the last digits of both number: 7*3 = 21. Write down 21

The product of 57 and 53 is thus 3021

Quick Multiplication By 4

To multiply any number times 4 at quick speeds, first double the number and then double it again. Let's use this shortcut with 1,223 times 4: Double of 1,223 is 2,446, and double 2,446 is 4,892. 4*1223 is 4892!