Long Multiplication

We have to calculate 436*54. We can write one number as the top row of a table as shown and the other number as the first column. We multiply an element in a row by an element in a column to get that element in the table.

*

400

30

6

50

20000

1500

300

4

1600

120

24

To find the element in the 3 rd row 3 rd column (shown in blue) we multiply 4 in the 3 rd row by 30 in the 3 rd column.

Then we add up all the answers in the table. We obtain:20000+1500+300+1600+120+24=23544.

Example: Find 456*24

*

400

50

6

20

8000

1000

120

4

1600

200

24

Then we add up all the answers in the table. We obtain 8000+1000+120+1500+200+24=10944