Hi BBDad,
Both DD and I have this, though it's much more associated with letters than numbers in our case. Dd's letter-colors and mine do not coincide, though a few of them are the same. They have textures, too.
I was amazed to find out that not everyone has this; DH doesn't and he just looks at us like we're crazy whenever we start to argue what color a particular letter is. Makes life more interesting, that's for sure! Reportedly it's more common among females than males. I do wonder if math-oriented folks have strong association with number-color and more verbal people tend towards letter-colors.
BTW, 7 is forest green, not orange.....
