Brain Age speedrun is absolutely spot on

Brain Age is a puzzle game to exercise your brain a little each day. You can play a variety of puzzles to train your brain, including stroop tests, mathematical questions, and Sudoku puzzles, all designed to help keep certain parts of the brain active. Although there has been controversy over the scientific effectiveness of the game in keeping your brain active, Nintendo has been careful not to claim the game has been scientifically validated, however stating that it is an 'entertainment product "inspired" by Dr. Kawashima's work' in the neurosciences. As far as we know, drawing doodles instead of the correct answers won't get you by the mind bending puzzles and questions it has to offer.

This run shows you how you can abuse the number recognition program by secretly drawing the number answer in each picture and exploit the stroke direction in the process.

via wired.com