sivuttaissummaa

Sivuttaissummaa is a Finnish term that translates to "lateral sum" or "sideways sum" in English. It refers to a method of summing numbers within a matrix or a grid where the summation is performed horizontally, row by row. This contrasts with a vertical sum, which would be a column sum.

In a typical matrix where numbers are arranged in rows and columns, a sivuttaissummaa involves adding all the elements within each individual row. The result of each row's summation is a single value representing that row's total. These individual row sums can then be presented alongside the matrix, often in a separate column to the right.

For example, if you have a matrix like:

1 2 3

4 5 6

The sivuttaissummaa for the first row would be 1 + 2 + 3 = 6.

The sivuttaissummaa for the second row would be 4 + 5 + 6 = 15.

The results would be presented as:

1 2 3 | 6

4 5 6 | 15

This concept is fundamental in various fields, including data analysis, accounting, and basic arithmetic exercises involving grids of numbers. It's a straightforward way to summarize the quantitative contribution of each horizontal segment within a larger dataset presented in a tabular format. The term emphasizes the direction of the summation, highlighting its horizontal nature.