abhi7605 wrote this blog titled "Multiplication of 4 digit by 4 digit"

Multiplication of 4 digit by 4 digit

step 1 : Multiply unit digit by unit digit

o  o  o  o

o  o  o   o

step 2 : Multiply nos. diagonally and add

o  o  o  o

o  o  o  o

step 3 : multiply the extreme nos. diagonally and the centre nos. and finally add.

o  o  o  o

o  o  o  o

step 4 : multiply the extreme nos. diagonally and the centre nos. diagonally and finally add.

o  o  o  o

o  o  o  o

step 5 : multiply the extreme nos. diagonally and the centre nos. and finally add.

o  o  o  o

o  o  o  o

step 6 : Multiply nos. diagonally and add

o  o  o  o

o  o  o  o

step 7 : Multiply nos. on extreme left

o  o  o  o

o  o  o  o

Example 1:

5 2 1 3 X

2 1 4 2

step 1 : Multiply unit digit by unit digit

5 2 1 3 X

2 1 4 2

                     6  

step 2 : Multiply nos. diagonally and add

5 2 1 3 X

2 1 4 2

                    ₁46 (1 will go as a carry) 

step 3 : multiply the extreme nos. diagonally and the centre nos. and finally add.

5 2 1 3 X

2 1 4 2

                ₁2₁46 (1 will go as a carry) 

step 4 : multiply the extreme nos. diagonally and the centre nos. diagonally and finally add.

  5 2 1 3 X

  2 1 4 2

                        ₂6 ₁2₁46 (2 will go as a carry) 

step 5 : multiply the extreme nos. diagonally and the centre nos. and finally add.

  5 2 1 3 X

  2 1 4 2

                     ₂6₂6 ₁2₁46 (2 will go as a carry)

  step 6 : Multiply nos. diagonally and add

  5 2 1 3 X

  2 1 4 2

                 ₁1₂6₂6 ₁2₁46 (1 will go as a carry)

step 7 : Multiply nos. on extreme left

  5 2 1 3 X

  2 1 4 2

            11₁1₂6₂6 ₁2₁46 (2 will go as a carry)

The final answer will be 11166246

Example 2:

5 2 0 1 X

1 0 3 2

step 1 : Multiply unit digit by unit digit

5 2 0 1 X

1 0 3 2

         2             

step 2 : Multiply nos. diagonally and add

5 2 0 1 X

1 0 3 2

        32                        

step 3 : multiply the extreme nos. diagonally and the centre nos. and finally add.

5 2 0 1 X

1 0 3 2

      432                         

step 4 : multiply the extreme nos. diagonally and the centre nos. diagonally and finally add.

5 2 0 1 X

1 0 3 2

  ₁7432 (1 will go as a carry) 

step 5 : multiply the extreme nos. diagonally and the centre nos. and finally add.

5 2 0 1 X

1 0 3 2

 ₁6₁7432 (1 will go as a carry) 

  step 6 : Multiply nos. diagonally and add

5 2 0 1 X

1 0 3 2

 3₁6₁7432

step 7 : Multiply nos. on extreme left

5 2 0 1 X

1 0 3 2

53₁6₁7432

The final answer will be 5367432

Example 3:

5121 X

2132

step 1 : Multiply unit digit by unit digit

5121 X

2132