I also have the habit of associating numbers with colours (see: Katy). 3 is yellow, 4 is orange, 5 is red, 6 is purple, 7 is grey. I'm not sure about the others.
A childhood belief about counting

others believed things like this
- I used to believe that people's brains differed in colours. I always wanted purple brains for some reason.— Katrina
- I used to believe that numbers had gender, that the odd numbers were boys and even numbers were girls. — Evelyn
- I thought "Orange is the New Black" was about wearing orange to funerals.Anon
- Tyler Perry and Katy Perry were both siblingsAnon
- i used to believe everyone saw different colours but just described the same.Anon
- I thought that the Chewit wrappers were different flavours as they were different colours like the sweets— Helen