INTRODUCTION
The word “equivalent” is one of the most useful in mathematics and one of the most abused in mathematics education. The implication is that this one is not all ACARA’s fault. Nonetheless, the fact that it was predictable that ACARA would make a mess of it doesn’t alter the fact that ACARA made a mess of it. So, here we are. And a warning: this is a long post; there seemed no way around it.