Pylväsmenetelmä

Pylväsmenetelmä, known in English as the column method or stacked multiplication, is a mathematical algorithm used for multiplying multi-digit numbers. It is a fundamental arithmetic technique taught in primary education. The method involves arranging the numbers vertically, one above the other, and performing a series of multiplications and additions.

The process begins by writing the multiplicand above the multiplier. Then, each digit of the multiplier is multiplied by each digit of the multiplicand, starting from the rightmost digit of the multiplier. The results of these partial multiplications are then written in rows, typically indented according to the place value of the multiplier's digit. For instance, when multiplying by the tens digit, the partial product is shifted one place to the left. Finally, all the partial products are summed vertically to obtain the final product.

The pylväsmenetelmä breaks down the complex task of multiplying large numbers into a series of simpler, single-digit multiplications and additions, making it easier to manage and less prone to errors. It relies on the distributive property of multiplication and the place value system. This systematic approach ensures that all necessary multiplications are accounted for and combined correctly. It is a widely adopted method due to its clarity and efficiency in manual calculation.