Click on this link to access an incredible Fun Maths Dictionary for Kids. It’s full of colour and has heaps of interactive activities which help explain different Maths concepts. It is arranged with an alphabetical index, like other dictionaries, but these are only MATHS concepts. Go in and have a look. This could be just what your child needs (and might help parents out of any tricky questions too…) 🙂
https://www.teachers.ash.org.au/jeather/maths/dictionary.html 
Canteen