Accurate, fluent verbal expression of mathematical equations is not a common skill, even in people who specialize in math and science. Therefore I often do a bit of training for my readers. To begin, I make sure they memorize the greek alphabet, learn the proper terminology, and know the correct order to read each of the phases in a long equation. Some instructions that I give them are very simple. For example, I ask them to make sure they name brackets and parentheses correctly. There are many such details that a sighted person breezes over because they are used to reading and writing math, not speaking it. Once I am confident about a readers ability, I might also assign them to record the equations in the articles/chapters to be added to to my library of recordings.
I have mathematical expressions recorded separately from the main body the text and saved in a separate file within the larger folder. It is helpful to have equations quickly accessible, rather than having to listen through the entire paper/chapter.