DS (6) is really struggling with remembering his number bonds, and I can see these are the key to him progressing with his numeracy at school. It's like he just switches off and he'll come up with the most ridiculous guesses and then gets really stressed out very quickly. I'm seeing little improvement over the course of a year or more so I'm after some ideas for practising this with him without him realising. Workbooks etc. are totally out, as is anything with obvious "sums" like flashcards, maths board games, etc. Something like "Junior Brain Training Maths Edition" for his Nintendo DS without ever mentioning the word Maths? DS is very astute and very good at picking up when he's being hoodwinked.
Any ideas very gratefully received!