Paid app ($0.99) — only Google Play can deliver it
After playing, you'll become a mental arithmetic master.
1020 – Offline Puzzle Game — description
1020 is a simple puzzle game! The numbers elimination gameplay is easy to learn and incredibly addictive! Drag and drop numbers — when three numbers add up to 10 or 20, they merge into one number. Eliminating three 10s or three 20s earns high scores and extra effects. Game scores accumulate as bonuses. Continuously building up bonuses is the key to achieving high scores!! Mastering the game will also improve your mental math skills.