I saw this on Keisers blog. < 1 min. No max.

We have this problem down here as well, but we call our problem "New Math" but basically the premise is the same. It is not about the result it is about the "narrative". The facts being that 3 x 4 = 12 is not so important is being able to tell a story about how you arrived at your incorrect answer.

Now in this video the woman says that they correct the child if they come up with the wrong answer but the most important part is the story or the journey through the math process. In australia the difference is that they, the class can come together and negotiate the solution. So by a consensus they all arrive at the preferred answer. As I hint at, it doesn't have to be the factual answer, just an answer that everyone can live with,