Hi pols:
I think toomuchicecream raises a good point - progress isn't linear (a straight line/ steady) - and in maths there can suddenly come a crunch point where recall of number facts (multiplication tables especially) or concepts (fractions/ percentages/ proportions/ mean/ mode/ median) can seem impenetrable.
My advice is consider trying to do more at home.
If your school subscribes to education city, manga high, sum dog, my maths or similar - keep using these resources over the summer. Even if your child just plays the games it keeps maths skills active and may even build skills.
If you're concerned that the issue is multiplication tables. Maybe they get the idea and can get there - but have no speed of recall and completely fall to pieces if presented with an inverse multiplication table fact - e.g. 36 divided by 9 is ?????
I would strongly recommend the games/ resources on multiplication dot com: www.multiplication.com/
Woodland Junior School Maths Zone has all sorts of links to games which can help with practically every topic in maths: resources.woodlands-junior.kent.sch.uk/maths/
If at core you feel that the issue is that fundamentally your DC doesn't understand concepts you might want to consider getting workbooks or joining an on-line tutorial - there's tons of on-line tutorials out there:
mathletics: www.mathletics.co.uk/
maths whizz: www.whizz.com/
komodo maths: komodomath.com/
mathsfactor: www.themathsfactor.com/
Have a look at what the programmes have to offer - many have videos explaining the programme/ trial lessons so you can get an idea. I'd encourage you to show it to your child and see if they like it.
DD1 was seriously struggling with maths at end of Y2 (barely able to add to 20 and unable to subtract). We started mathsfactor and have never looked back. Others here have posted similarly that maths whizz/ mathletics/ komodo maths have all been great help.
I think the point is that your DC is a bit stuck - and oddly enough practice/ patience/ and a bit of detective work on your part to get to the bottom of what the issue is - can all make a huge difference.
It's a long summer - so my advice is determine to use a small portion of most days toward maths. Try to encourage variety - but encourage your child to do a bit of maths every day. Practice really does make a big difference.
HTH