Sum Method Followed by Maximum Method: This diagram shows the following calculations in a grid format:
Row 1: 4+4+na=8
Row 2: 1+8+6=15
Row 3: 2+3+7=12
Column 1: Maximum of {4, 1, 2} is 4
Column 2: Maximum of {4, 8, 3} is 8
Column 3: Maximum of {na, 6, 7} is 7
Column 4 (aggregates from SUM): Maximum of {8, 15, 12} is 15