Here are a couple of links to websites that may be useful for maths and spelling activities a home:

'Maths is fun' offers good step by step instruction on all the numeracy topics, as well as practice questions and examples.
http://www.mathsisfun.com

The children in KS2 have a sumdog account which is accessable at home.
https://www.sumdog.com/

This spelling based website offers advice and activities to help with spelling.
http://www.spellitright.talktalk.net/

BBC Bitesize also offer a good selection of resources that help in a number of curriculum areas.
https://www.bbc.com/education/levels/zbr9wmn

Primary Homework Help is an excellent site that offers child friendly support on numerous topics.
http://primaryhomeworkhelp.co.uk/