I don't know if anyone else has come across these, maybe they are a normal part of the curriculum in mainstream English schools? But I've just heard that a 9-year-old relative had one at his school in the South of England.
Basically, all the children in his class had to go (on their own) to the head teacher's office and verbally answer some mental arithmetic questions, they were given three seconds to answer each question. They got to chose when they wanted to do it, but they all had to do it.
Now, maybe its just me, but that sounds horrendous. I'm quite good at maths, but I'm sure I would do extremely badly under those conditions. My relative did really well, and his parents are proud of him, and its great for him that he's had a boost to his self esteem, but he's always been very good at mental arithmetic, its one of his strengths. When I think of my arty, creative, dreamy daughter having to go through that I just know that she would not only do very badly in terms of getting lots of questions wrong, but also become really anxious and very worried about the whole thing. There must be loads of kids whose brains just aren't wired to do well in situations like that, how many will come away thinking "I must be rubbish at maths" ?
Surely the most important thing with maths is to understand how to work things out, and the best way to do that is to apply it to real life. I can see that certain specific occupations might require people to have skills in quickfire calculations, but how is that relevant to a class of 9 and 10 year olds? If ever I heard of a good way to put more kids off maths - this is it!