. It can be observed that spontaneously, a young child does not count even if she knows a sequence of number names. From this general situation, several steps can be conceived, taking into account didactical variables (Brousseau1997) – that is, conditions on the tasks to be achieved that ...
now called peroxide of manganese, ought perhaps, in anticipation of its being some day related to salt-like derivatives, to be called permanganic acid.” In modern usage MnO2 is not a peroxide (dioxide(2–)) and the term permanganic acid would generally be taken to mean HMnO4 (not H2...