numbers 1-9 in a figure - All-Russian MO 1998 Regional (R4) 8.5
Source:
September 17, 2024
combinatorics
Problem Statement
Place numbers from to in the circles of the figure (see Fig. ) so that the sum of four numbers, finding located in the circles at the tops of all squares (there are six of them), was constant ,
https://cdn.artofproblemsolving.com/attachments/8/8/5fe1e8c5949903dd9500b992c8139277cebe7f.png