Mathematics can be used to study Sudoku puzzles to answer questions such as "How many filled Sudoku grids are there?", "What is the minimal number of clues in a valid puzzle?" and "In what ways can Sudoku grids be symmetric?" through the use of combinatorics and group theory.

That's completely different from a Sudoku puzzle itself or the process of solving one.

Sure, it's math in the way that everything can be described using math, but you wouldn't explain 'purple' as "the math of calculating what volume of blue to add to a given volume of red in order to reach the desired hue."