The long multiplication method is a method of multiplying two numbers that are difficult to multiply normally but can be multiplied easily. For example, we can easily find the product of 55 × 20 by multiplying 55 by 2 and then adding a 0 at the rightmost place of the answer. 5× 2 = 10 and 50 × 20 = 1000. To find more tricks like this refer to 1 to 100 squares and cubes
What is a good method to learn long multiplication?
There are several easy ways to do it.
1. Long Multiplication Method by 10
1.1 Multiply the non-zero part of the numbers.
1.2 Count the zeros in each factor.
1.3 Add the same number of zeros to the product
2. Long Multiplication Method by 5
1.1 Multiply the number by 10
1.2 Divide the product by 2
3. Long Multiplication Trick by 999
This multiplication trick can be applied with any number of 9’s. Considering the multiplication of 248 x 999
1.1 Subtract the other number by 1 with whom 999 is multiplied
1.2 Write down on left side
1.3 subtract the number from 999 and write down on right side
For more examples please check out the video below.
4. Long Multiplication by 111
This multiplication trick can be applied with any number of 1’s. Here we will try to write down the multiplication from right to left. Multiplying 62 with 111
1.1 Take the right most digit of number other than 111 and write it down
1.2 Add the digits(Number apart from 111 i.e. 62 in this case). The addition here is 8. Write it down.
1.3 Write down the left-most digit as it is
For complete example refer to link below