Sumaddle

• “The ONLY iOS game I've never gotten tired of”, Reddit review Apr 2024

• “This is, hands down, THE best logic game on the App Store”, US App Store review Mar 2023

• “Best brain workout”, US App Store review Jan 2023

Known in the puzzling community by the names Doppelblock and Smashed Sums, this type of logic puzzle first appeared in the Japan Puzzle Championship 2006. On paper, the puzzles can be mind-blowing to solve, but the Sumaddle app adds the essential element of interaction to transform them into intriguing brain teasers that unfold before your eyes.

Take your time and enjoy puzzling your way through more than 120 free puzzles, ranging all the way from easy to very difficult. If you get stuck or make a mistake, the built-in help will get you going again. The help explains the logical reasoning at each step, making it a great way to learn how to solve the puzzles. Use the help as much as you like, it’s also completely free. Even with so much free content, you won’t be bothered by ads - Sumaddle is completely ad-free!