Vertical Abacus is an educational game developed by Rarepeak juegos y entrenamiento mental for the Android platform. It is designed to help children and the elderly learn numbers in a fun and easy way. The game comes with Montessori colors and offers a range of features to help users learn the concepts of units, tens, hundreds, thousands, tens of thousands, and even basic arithmetic operations like addition and subtraction.

The game's interface is user-friendly, with a touch-based system to add or remove balls from the abacus. When a user reaches 10 balls in a column, they must remove all the balls and add one to the next column to the left. The balls move to indicate that the column has reached its limit. Users can also change the sign from addition to subtraction, reset the abacus to a random number, or use the right and left arrows to add or remove units. Holding the arrows down allows users to fast forward or rewind.

Overall, Vertical Abacus is a great learning tool for children and the elderly. It offers a fun and interactive way to learn numbers and basic arithmetic operations. The game is available for free and provides a great way to keep the mind sharp while having fun.