**CERME 7: Working Group 2**

**Teaching and learning of number systems and arithmetic**

**Leaders **

Susanne Prediger (Germany) prediger@math.uni-dortmund.de (Chair)

Nada Stehlikova (Czech Republic), Joke Torbeyns (Belgium),

Marja van den Heuvel-Panhuizen (The Netherlands)

**Papers**

- Marilena Chrysostomou / Chara Tsingi / Eleni Cleanthous Cyprus: Cognitive styles and their relation to number concepts and algebraic reasoning
- Lisser Rye Ejersbo / Morten Misfeldt:Danish number names and number concepts
- Elvira Ferreira / Lurdes Serrazina: Strategies and procedures: what relationship with the development of number sense of students?
- Anatoli Kouropatov / Dina Tirosh:Is it inevitable to narrow the interpretation of the equal sign? Preschool children's understanding of equality
- Dietmar Kuechemann / Margaret Brown / Jeremy Hodgen: Using the double number line to model multiplication
- Anna Lundberg:Proportion in mathematics textbooks in upper secondary school
- Hartwig Meissner:Teaching arithmetic for the needs of the society
- Carol Murphy:Analysing children’s learning in arithmetic from a socio-cultural perspective
- Aristoklis Nikolaou / Demetra Pitta-Pantazi: A new theoretical model for understanding a concept of elementary school mathematics: the case of fractions
- Ildikó Pelczer / Cristian Voica / Florence Mihaela Singer: Between algebra and geometry: the dual nature of the number line
- Marjolijn Peltenburg / Marja van den Heuvel Panhuizen: Special education students’ ability in solving subtraction problems up to 100 by addition
- Sebastian Rezat: Mental Calculation Strategies for Addition and Subtraction in the Set of Rational Numbers