| 234 |
|
7900 |
| 117 |
15800 |
15800 |
| 58 |
|
31600 |
| 29 |
63200 |
63200 |
| 14 |
|
126400 |
| 7 |
252800 |
252800 |
| 3 |
505600 |
505600 |
| 1 |
1011200 |
1011200 |
| PRODUCT |
1848600 |
|
Set up a 3-column table as above. In the first row and column place the smaller of the two numbers: 234.
In the first row of the last column place the other number: 7900.
The other rows in the first column contain half the number in the previous row, ignoring any remainder. When the number gets to 1, stop filling the rows.
In the third column each of the other rows contains twice the number in the previous row until you reach the 1 in the first column.
For every row in the first column containing an odd number (highlighted in red), copy the corresponding number in the last column into the second column.
Now, add up all the copied numbers in the second column. The result is the product of 7900×234=1848600.
This method effectively uses binary arithmetic to work out the decimal product. It can be applied to any two integers.
