First of all i would like to tell you that this trick will be applied under some restrictions.
- The first digits of both numbers must be the same
- The sum of last digit of numbers must equal to 10
Lets Understand this trick with some examples:-
Example 1:- 26 x 24
- Start by taking first digit of the first number and multiply it by one more than it which will give you first digit(s) of the answer. That is 2 multiplied by (2+1) = 6. It means that 6 is the Most significant digit of the answer.
- Now multiply last digit of both the numbers i.e., 6 x 4 = 24.
Combine the result of step 1 and step 2 and the answer for 26 x 24 = 624.
Example 2:- 47 x 43
- Do similar as we have done above i.e., multiply first digit of first number with one more than it. Hence 4 x 5 = 20. 20 is the MSD (Most significant digit) of the answer.
- Multiply last digit of both the numbers 7 x 3 = 21
Combine the result of step 1 and step 2 and the answer for 47 x 43 = 2021.
This trick can also be applied on 3 digit number as well. Lets take an example
Example 3:- 132 x 138
- Multiply 13 by one more than it i.e., 13 x 14 = 182. Hence 182 is MSD (Most Significant Digit) of the answer.
- Multiply last digit of both the numbers 2 x 8 = 16.
Combine the result of step 1 and step 2 and the answer for 132 x 138 = 18216.
To multiply by 9,try this:
(1) Spread your two hands out and place them on a desk or table in front of you.
(2) To multiply by 3, fold down the 3rd finger from the left. To multiply by 4, it would be the 4th finger and so on.
(3) the answer is 27 … READ it from the two fingers on the left of the folded down finger and the 7 fingers on the right of it.
This works for anything up to 9 x 10
In case you have any doubt regarding above tricks please let us know in the comment box below.