How to represent a translated formula in an accessible and visually clear way?

I'm working on porting a website copy from old system to new. One item of content has me flummoxed as to what to do with it.

It is a mathematical formula, written in english. However, it is saved as an image. (Note: this is just an example; it's not actually a valid formula).

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Now, I could translate this to pure text, but that wouldn't really be as useful to fully-sighted users (i.e. the majority) because it would be something like this:

Fee = 'Total account balance as of 12 Jan' * 'Interest rate %' * ('Days in the current month' / 'Full length of service in days')

This is accessible, but isn't exactly usable anymore as it is worse than the current solution for sighted users.

I could provide this text breakdown as the alt text of the image, but that's not really that appropriate either, because it's very long and not really what alt text is designed for.

So. How do I translate this pure-text image into something still clear and understandable to look at, while being accessible at the same time?