Are nerf test questions similar to the numeracy part of CATs.
If so they are nothing like as good a test of maths ability as teachers seem to believe.
They do test being able to do quick puzzles using some mental arithmetic skills and whether you think like the question setter.
DD1 got 97 in Y7 and around 110 (can't remover exactly) in Y9 cats.
She's at the very top of set 2 for maths and I'd be surprised if she doesn't get an A.
She won't get A* because she's dyslexic and even with 25% extra time she'll be pushed to finish.
And that is the problem with CATs and I suspect nerf tests, if your processing speed, working memory (no scribbling paper) and instant tables recall aren't good they are really pressured.
Doesn't bear any relationship at all to your ability to understand rearranging equations, negative numbers or even differential equations, just fucks up doing one stupid little test that makes you spend Y7 in set 3 maths staring at the wall, doing L4 again and being the TA for set 3 science 
No DD1 and I don't trust, standardised 'maths' tests