We started using Maths Whizz which is an online tutor.
You initially do an assessment where it asks various questions and then decides the level of maths you understand and presents lessons from a starting point.
It breaks the curriculum down into approx 17 different topics and will give an explanation, 10 questions and then a test on each topic. It then moves onto another topic. If you pass you move on, if you fail, it will bring up the subject again at a lower age and move on from there,
I have found it fantastic for filling in the gaps and explaining strategies that I certainly wasnt aware of.
It matches the UK National curriculum and covers questions in all areas.
It recommends spending a minimum of 30 and maximum of 90 minutes a week, which, if broken down as 15 minutes a day is very manageable.
It works like a tutor, and if you get a question wrong, it will break down the question into stages.
Its very clever and I have found it invaluable for filling in gaps (that I wasnt even aware of)
It works on a maths age which can work positively or negatively depending on your child, so its best not to focus on this.
Its definitely worth a trial, especially if you are willing to pay for a tutor.
There are extensive tutoring resources online but you have to make the commitment of putting time aside to do it, just like you would by going to an external tutor.