Vol. 42 Num. 1 (2022) - front cover0 Jérôme Proulx Conceptualiser le périmètre ABSTRACT 2 Christopher Danielson Communication: Response to 'Conceptualiser le périmètre'9 Ali Barahmand Communication: Zero probability and dimensional confusions9 Luis Felipe Prieto-Martínez Communication: Moser's worm problem: an unsolved problem in plane geometry11 Igor V. Andrianov Communication: Why would a biologist need a logarithm?11 Tye G. Campbell , Haley H. Parker , Anna Keefe Communication: Explicit instruction or poor realizations of dialogic instruction: which is better?12 Nicole Maher , Helen Chick , Tracey Muir Communication: Horizon knowledge and the complexities of contingency: a scenario from a senior secondary mathematics classroom15 Anna Sfard Communication: It's all Chinese to me – and it makes a lot of sense: a letter to Dave and David17 Josh Markle Tentativeness as strategy and affordance in spatial visualization ABSTRACT 20 Svanhild Breive , Merrilyn Goos , John Monaghan Interpreting a kindergarten episode through three perspectives on agency ABSTRACT 25 Frederick A. Peck Finding learning in ‘off task’ behavior: artifacts, agency, and second stimuli ABSTRACT 31 David Wagner Subject to mathematics ABSTRACT 35 - Contributors40
