We (the NBA committee on UEB Technical Material) touched on this kind of situation in the 2020 workshop "Spatial Problems, Rules and Advice," especially on slides 48 and 49. A full recording of that webinar is available from NBA's page on Web-based Learning.
What we suggest is:
When print uses a tiny number to increase the value of a number by a power of ten (e.g., in “borrowing”) place that number on the line above the number whose value it increases, and align digits by place value.
A lack of @: can tell the reader that the number above is meant to combine with and not replace the number below.
A screenshot of a problem transcribed following that advice is attached. In the attached .jpg and .brf are that same problem as well as some of your samples transcribed in what we think is an accurate and practical way.
Does this help?
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