Seeing things as colors is really questionable. Why do we see them? For example “ Math is blue and English is red”. It seems and feels accurate. I know that this topic is controversial but still there are some agreements. But it's more than that.
If somebody mentions the number 7 I would think of Thursday, orange and fall. And surprisingly some people do too. Also Friday, number five and blue. But if i start to go further more, let's say physics is purple and number 2 is a girl. Now, not everyone will agree with me even though I feel like this makes sense. It's not just colors that we describe certain things with. It could be gender, seasons, or shapes etc. We can describe people with these as well for example. “He is built like the number 6”…
This topic has nothing beyond that, it's just something interesting to think about. It could just be more of an “opinion” and maybe trying to describe something to see them better. We might get the ideas from what we saw or remember it as.