A Tangible Math Game for Visually Impaired Children
Ana Cristina Pires, Sebastian Marichal, Fernando Gonzalez-Perilli, Ewelina Bakala, Bruno Fleischer, Gustavo Sansone, Tiago Guerreiro · 2019 · Proceedings of the 21st International ACM SIGACCESS Conference on Computers and Accessibility (ASSETS) · doi:10.1145/3308561.3354596
Summary
This demonstration paper presents iCETA, an inclusive interactive system for math learning that enables visually impaired children to autonomously engage with and solve additive composition tasks (addition and subtraction) through tangible interaction. The system was designed through participatory sessions with visually impaired children and their educators in Uruguay. iCETA uses physical tangible blocks representing numbers 1 to 5, where each block encodes the number through multiple simultaneous representations: the physical size of the block (proportional to the value), Braille markings, high-contrast colors, and audio feedback when placed on the interactive surface. Children solve math tasks embedded in a computerized game by placing the correct combination of blocks on an RFID-enabled board. The system detects which blocks are placed using embedded RFID tags and NFC readers, then provides haptic feedback (vibration) and auditory feedback (speech and sounds) to communicate whether the answer is correct, partially correct, or incorrect. The game presents tasks as a narrative — a rocket ship needs fuel (the correct sum) to launch — providing context and motivation for the mathematical activities. The design follows principles of embodied cognition, where understanding abstract concepts like numbers is scaffolded through physical manipulation and bodily experience with proportionally-sized objects.
Key findings
The system was developed iteratively with input from educators at a school for visually impaired children in Montevideo, Uruguay. The participatory design process revealed several important requirements: children needed multiple representations of numbers simultaneously (not just one modality); the physical proportionality of blocks to their numeric value supported understanding of number magnitude; and the game context was important for sustaining engagement. The tangible blocks were 3D-printed with embedded RFID tags, with sizes ranging proportionally from smallest (1) to largest (5). The interactive board contains NFC readers that detect block placement and communicate with a tablet computer running the game application. Audio feedback includes spoken numbers when blocks are placed, encouragement for correct answers, and guidance for incorrect attempts. The system supports inclusive use — sighted children can play alongside visually impaired children using the same blocks and game, with visual elements (colors, screen display) complementing the tactile and auditory channels. The combination of tangible interaction with digital game elements aims to provide the scaffolding that traditional abstract math instruction often lacks for children with visual impairments.
Relevance
This work addresses a significant gap in STEM education for visually impaired children: the difficulty of teaching abstract mathematical concepts like number composition when traditional visual teaching aids (number lines, manipulatives with printed digits, worksheets) are inaccessible. The multi-representational approach — encoding each number through size, Braille, color, and sound simultaneously — reflects the principle that mathematical understanding is deepened when concepts are experienced through multiple modalities. For accessibility practitioners working in educational technology, iCETA demonstrates several important design principles: tangible interfaces lower the interaction barrier for young children who may not yet be proficient with touchscreens or keyboards; proportional physical size creates an embodied, intuitive understanding of numerical magnitude; inclusive design (usable by both sighted and visually impaired children together) supports integrated classroom settings; and gamification provides motivation for repetitive practice that is essential for mathematical fluency. The participatory design approach with educators ensures the system fits real classroom needs rather than being a technology-driven solution looking for a problem. The use of affordable technologies (3D printing, RFID, NFC) makes the approach replicable in resource-constrained educational settings.
Tags: visual impairment · children · mathematics accessibility · tangible user interface · inclusive design · STEM accessibility · Braille · haptic feedback · gamification · participatory design · educational technology