That book looks like quite a challenge. For pages 167 and 168, I would not try to connect those notes with arrows to the spatial problem. After the spatial subtraction problems, I would list the comments detailing what is done. They are self descriptive. Trying to put them on the same line as the elements to which they refer, or drawing arrows connecting them to such elements, would make the example unreadable.
I am still thinking about page 107. I welcome suggestions from anyone who might have an idea for representing the concept shown. I will try out a couple of things and get back to you. Did you yourself come up with something that could work?