The relationship between external and mental number representations is highly relevant to mathematics education. Mathematics teachers commonly use various number representations, such as symbolic notation or a set of items, to help students learn numbers. In addition, psychological research suggests that the use of specific external number representations can help learners develop a mental representation of numbers.

Obersteiner will elaborate on the relationship between external and mental representations of numbers, and present the results of two empirical studies. The first study explored first graders’ efficiency in using a grid of 20 items. The second investigated educated adults’ strategies in comparing the numerical values of two fractions represented as symbols. Both studies used written tests and analyzed the participants’ reaction times and eye movements to assess their performance and strategy.