Peasant multiplication is an old
algorithm for
multiplication. It requires no use of a
multiplication table; however, it requires that the user be able to
divide by 2. The user must also know how to
add.
- Write the two numbers (A and B) you wish to multiply, each at the head of a column.
- Starting with A, divide by 2 until there is nothing left to divide. Write the series of results under A.
- Starting with B, keep doubling until you have doubled it as many times as you divided the first number. Write the series of results under B.
- Add up all the numbers in the B-column that are next to an odd number in the A-column. This gives you the result.
Example: 27 times 82
| A-column | B-column | Add this |
| 27 | 82 | 82 |
| 13 | 164 | 164 |
| 6 | 328 | |
| 3 | 656 | 656 |
| 1 | 1312 | 1312 |
| Result: 2214 |