Place the digits 1-6 once each in every row and column. Every cell has exactly two orthogonal neighbours that differ from it by at least 3. On the grey line, one cell is the sum of the other two.
Place the digits 1-6 once each in every row and column. Every cell has exactly two orthogonal neighbours that differ from it by at least 3. On the grey line, one cell is the sum of the other two.