Welcome to Rullo, the math puzzle that’s so simple, even your pet goldfish could give it a shot—provided it has opposable fins! You’ve got yourself a board packed with numbers, and your mission, should you choose to accept it (which you totally should, because it’s way more fun than cleaning your room), is to make the sum of every row and column match the magical number in the box. Think of it as a math party where you’re the bouncer, kicking out unwanted numbers by clicking on them like you’re swiping left on bad Tinder dates.

The board comes in sizes that range from cozy 5×5 to spacious 8×8, because who doesn’t love a little extra space for their mathematical genius to spread out? And if you’re feeling spicy, Rullo offers three levels of difficulty: 1-9 (for those who think numbers are just a suggestion), 2-4 (for the serious strategists), and 1-19 (for the daredevils who like to live on the edge of numerical chaos). In the 1-9 level, expect numbers to be as cute as a puppy, but don’t let their adorableness fool you—each click brings you closer to math glory!