If your daughter is mainstream school talk to the SENCO, otherwise talk to her teacher as these should be able to give you ideas on how best to help your daughter.
These suggestions probably work better for a younger child, but are all ones I used on my daughter.
First of all forget about teaching your daughter 'maths', leave it to the teacher. What you can do is make maths fun and part of her life.
Cooking: This is a fantastic way of introducing your daughter to several mathematical concepts, weighing, measuring and time. At the same time she is learning to cook, read, follow instructions, with the added bonus of something tasty at the end to eat.
Finding shapes while out. I played this with my daughter, picking a different shape and see who can find the most first.
Another favourite was playing simple games like snakes and ladders and Ludo, I also got rid of the six sided dice and used 10 sided dice to make life easier, they can be found online for a few quid. Don't be afraid to adjust the rules a little. So for example on Ludo you have to throw a 6 to get a piece on the board, we would use any number larger than 6.
A huge favourite was making our own card games. For example using index cards we made our own version of Fish. The beauty of this was we had great sessions of craft, creating our own card sets, then playing cards with her own unique set. These were usually with 52 card, 4 different colours and then shapes, pictures or numbers. As I recalled the kings were all power rangers, using their colour as the theme for that suite. 1 was a dinosaur, printed and then coloured in the relevant colour, and so on. These were either printed, coloured and glued to the index card, or drawn straight on the card. Another thing she loved was I would print her photo out and pasted it onto the back of each card.
Personally I never bothered with buying books. I did however subscribe to Enchanted Learning website. For less than £20 per year it gave access to thousands of worksheets covering a wide range of topics and activities for different ages and stages. These gave me the confidence to start creating my own for my daughter. My daughter loved this site and would regularly pick ones to do, as well as what we printed for her to use. Unlike a book you can print when ever you want so the same sheet can be done several times.
The more you can make things part of your daughters life the easier it will be for her at school. The more you do together the easier it will be for you both to think of new ideas.
As an individual I stood alone.As a member of a group I did things.As part of a community I helped to create change!