First off lifeissobusy - have a look at this page from MN on progress through NC levels (www.mumsnet.com/learning/assessment/progress-through-national-curriculum-levels) - the table at the bottom of that page shows that for a notional 'average' child NC L3b is expected progress at end of Y4.
So my advice is that what you should be starting out with is a feeling that your child is doing o.k. - not great - but o.k. - she's where she should be.
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lacking confidence academically or otherwise (but especially as you indicate this is an issue for you) - can really hold a child back. So you need to remind yourself that your her cheerleader: You can do it! Yes you can! (as Bob the builder would say). I don't know that I'd go as far as Yoda (There is no try....only do!) - but said in a Yoda voice it usually gets a laugh from my girls.
My advice would be to talk with the teacher about things like:
What should we be working on at home? is always a great start.
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Resources for Year 4:
Woodlands Junior School Resources: resources.woodlands-junior.kent.sch.uk/ - particularly recommend maths zone/ literacy zone/ homework help (ideas of researching historical periods/ geograph/ etc...) - all free, friendly website, easy to find the bit you need and lots of resources/ links to games once you get there.
MULTIPLICATION is key in Year 4 - your DD really does need to be learning those times tables off by heart. You can chant/ sing/ etc... - but if like my DD your DD would rather not - try video games:
Multiplication on Woodlands Junior Maths Zone: www.primaryhomeworkhelp.co.uk/maths/timestable/index.html
Multiplication.com (advice & games): www.multiplication.com
and once they sort of know tables but are a bit shaky - download the free version of timez attack (2 platforms) which gives lots of practice of times tables and really helps build up speed (it will test your DC and start from where they're at): www.bigbrainz.com/
Knowing your times tables makes all further maths so much easier and really helps when you start to play with percentages, proportions & fractions.
We found the St. Ambrose spelling pages very useful for learning basic spelling patterns/ rules: www.saintambrosebarlow.wigan.sch.uk/spellingpage.htm - there are spelling books - but we just played their on line games. Warning - a few don't automatically mark answers - so you may need to help there.
Woodlands Junior school Literacy pages also very useful: www.primaryhomeworkhelp.co.uk/literacy/
READ - READ - READ - it's so beneficial. Read to your DD/ have her read to you. Talk about the stories/ the characters/ the author's use of words/ what words mean/ words you like/ etc.... But just encourage her to enjoy a good book. It's such a pleasure in life anyway - but it really helps at school.
MN have put up some free e-books on their learning pages - www.mumsnet.com/learning/learning-zone/key-stage-2-ebooks
Oxford Owl - now do free e-books for KS2: 9-11 selection link here: www.oxfordowl.co.uk/for-home/reading-owl/find-a-book/library-page?view=&query=&type=book&agegroup=6&book=1&booktype=all&series=all#
Magazines, comic books/ graphic novels and even video games (Professor Layton/ Pokemon/ other games with a lot of reading necessary to play the game) can also be of help.
Finally I don't know what to advice about your DD not liking school - this is something you really need to discuss with her. I think you need to sort out whether she finds school work 'hard work' and doesnt' enjoy it/ finds it stressful or whether it's more a social thing (maybe getting teased/ doesn't have many friends/ etc...). I can't really advise what to do for best - but you have my sympathy it isn't easy when your child isn't thriving - no parent enjoys seeing that. However, there are only 2 more years and then it's off to senior school - and that can be a major improvement.
All the best of luck with everything. PSBD