PYTH 40(1)_Contents.indd Open Accesshttp://www.pythagoras.org.za Index i ISSN: 1012-2346 (print) ISSN: 2223-7895 (online) Editor-in-Chief Alwyn Olivier Stellenbosch University (retired), South Africa Associate Editors Anthony Essien University of the Witwatersrand, South Africa Faaiz Gierdien Stellenbosch University, South Africa Michael Murray University of KwaZulu-Natal, South Africa Rajendran Govender University of the Western Cape, South Africa Editorial Board Jill Adler University of the Witwatersrand, South Africa Bill Barton University of Auckland, New Zealand Marcelo Borba São Paulo State University, Brazil Doug Clarke Australian Catholic University, Australia Jeremy Kilpatrick University of Georgia, United States of America Gilah Leder La Trobe University, Australia Stephen Lerman Southbank University, United Kingdom Frederick Leung University of Hong Kong, SAR, China Liora Linchevski Hebrew University of Jerusalem, Israel John Malone Curtin University, Australia Andile Mji Tshwane University of Technology, South Africa Willy Mwakapenda Tshwane University of Technology, South Africa John Olive University of Georgia, United States of America David Reid University Bremen, Germany Paola Valero Stockholm University, Sweden Renuka Vithal University of the Witwatersrand, South Africa Anne Watson Oxford University, United Kingdom Volume 40 Number 1 December 2019 ‘Semiregular tiling 3-4-6-4 (Small rhombitrihexagonal)’ by R.A. Nonenmacher. Retrieved from https://commons. wikimedia.org/wiki/file:tiling_ semiregular_3-4-6-4_small_ rhombitrihexagonal.svg Page i of ii Information for Authors and Readers Original Research Social science students’ concept images and concept definitions of anti-derivatives Eunice K. Moru, Makomosela Qhobela Towards validation of a rational number instrument: An application of Rasch measurement theory Jeremiah Maseko, Kakoma Luneta, Caroline Long Comparison of geometric proof development tasks as set up in the textbook and as implemented by teachers in the classroom Lisnet Mwadzaangati The use of semiotic representations in reasoning about similar triangles in Euclidean geometry Ifunanya Ubah, Sarah Bansilal Using standard setting to promote meaningful use of mathematics assessment data within initial teacher education programmes Qetelo M. Moloi, Anil Kanjee, Nicky Roberts The standard written algorithm for addition: Whether, when and how to teach it Nicky Roberts A commognitive perspective on Grade 8 and Grade 9 learner thinking about linear equation Anthea Roberts, Kate le Roux Mathematics teachers’ levels of technological pedagogical content knowledge and information and communication technology integration barriers Gabrielle de Freitas, Erica D. Spangenberg Keeping sites in sight: Conversations with teachers about the design of toolkits peculiar to a continuous professional development initiative Faaiz Gierdien, Charles Smith, Cyril Julie The professional development of primary school mathematics teachers through a design-based research methodology Piera Biccard Webs of development: Professional networks as spaces for learning Kenneth Ngcoza, Sue Southwood Book Review Book review: International reflections on Realistic Mathematics Education Stanley A. Adendorff Correction Erratum: A commognitive perspective on Grade 8 and Grade 9 learner thinking about linear equation Anthea Roberts, Kate le Roux Reviewer Acknowledgement Guidelines for Authors ii 1 13 25 39 49 63 80 95 108 119 129 136 139 140 141