Rules and solutions Irregular Sumdoku 9x9 4 (Sums Sudoku, Sums Number Place, Samunamupure, Kikagaku Nampure) solve free online
The more “numerical” variant: to solve it, numbers can no longer be considered only as symbols, but it is necessary to count.
Fill in all the boxes so that every row, every column and every 3×3 sector contains all the numbers from 1 to 9, without any repetition.
The peculiarity of this variant is that it contains a series of "zones" identified by a border and a numeral in the upper left corner: adding the numbers contained in each zone (which are necessarily all different) it is necessary to obtain exactly that numeral.