Unless it is an Indy style test with no multiple choice use the advantage that having multiple choice gives.
Depending on the style of question some can be quickly ruled out and part of the problem worked through to them pick from a couple of possible answers.
Have excellent mental maths to do time tables and number bonds
Know the shortcuts like 98p can be treated as £1.00 which is far quicker and easier to handle but remember that 2p in the final reckoning.
Work out what type of question is taking the most time and work on that. If it really can’t be overcome then play to strengths and learn to skip the question
If run out of time then mark the outstanding questions with an answer even if a guess
DD was doing the letts ten minute tests in half the time and still found Kent and Bexley pressured so working on speed will really be a huge help. Saying that in the year she did Kent she missed out 7 questions (they now have fewer questions in the Kent test I understand) but her accuracy was 100% on those she did answer so she actually scored quite well so it isn’t always the perceived disaster if they don’t finish.