Abacus is a focused authoring tool designed with Geogebra 5.0 software. It combines dynamically the decimal system of numbering and the analysis and synthesis of numbers from a plurality of digits with the symbolic and verbal representation of these numbers. 84 micro-experiments have been developed with the Abacus, which are uploaded in Photodentro, the official repository of Ministry of Education

Selected Examples:

The following examples are availiable only in the greek language:

• Guess the number
• Column swap
• Absrtaction with Abacus
• Addition of three-digit numbers
• Which number is bigger?