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Bond books; making sure she knew her times tables inside and out; and making sure she understood how times tables relates to factors/multiples. The basis of most "tricky" primary school maths. For some reason our school did not teach this intensively. So later, things like adding and subtracting fractions, or working out ratios/proportions seems difficult.
We ignored the teacher about reading "the classics." She hated them all and reading the classics = no reading. I scoured book lists to find ideas on books she might like and let her read anything she wanted to read. We kept to an early bedtime with the proviso she could stay up 30min to an hour to read if she wanted to do so. That way there was built in reading time. Obviously, we are one TV in the living room family and she didn't have any hand held computers to revert to instead.
Finally, we wanted to send her to a selective private school and we realised that her writing wasn't great. So in a last minute panic (6 months before exams) we got a writing tutor. This lady was pure gold and our DD learned a lot from her. DD never would have listened to us. We ended up paying for 13 hours worth of tutoring. We were against it at first, but I have to admit DD really blossomed. We were so impressed, we tried to find a maths tutor too. (Yes we really did change our mind whole heartedly about tutors.) But we never found anyone decent. So we did old admissions papers with DD ourselves, bottoming out any concepts that she was missing.
That 6 months of 11+ prep, must have benefitted her generally. But it wasn't focussed on SATS it was focussed on private school 11+ admissions. DD said that SATs maths was much easier, but that the level 6 reading comprehension paper was just as difficult.
Phew, that's a looong answer, but I wanted to be straight with you. In short, I think if you are staying within the state system, then just making sure they get hooked on reading and really understand their times tables/factors/multiples will be enough. If you live in London and want to have a go at the selective private schools, that would just be a foundation.