Fast Track Multiplication Techniques or Tricks

Trick 1
When a number (N) is multiplied by 9,99,999,… or (10ⁿ -1).

In such cases, number of zeros equal to number of 9s in (10ⁿ -1) are put extreme right of N to make a new number M and then N is subtracted from this new number to get the result. Clearly, (M - N) is the result of multiplication.

Example- Multiply 6243 with 999.

Solution. Here, N=6243, (10ⁿ 1)=(10³ -1) = 999

According to the rule,

                                                (N)       (M)      (N)

                                    6243*999=6243000 - 6243

                        999 has three 9s and hence

                        Three zero are put at the right

                        End of N to make M.

N is subtracted from M

To get the result

Of multiplication.

Therefore- (M-N)=6236757