This transcription is UEB with Nemeth. Many equations have numbers in light gray boxes. I’ve attached a screen shot of one example. Am I on the right track? I really don’t see any examples like this in the lessons or codebook. I only see examples of a single digit inside a box, but not as a part of an equation.
I would just ignore the boxes. The text explains what the reader is looking at. However, if you decide to retain the boxes, you should use the rules for shapes with interior modifications (which is what you did).