Writing must convey the general approach to the problem clearly and concisely in non-technical terms as well as describe very technical ideas in detail.
Mathematical proofs are similar to prose essays for any subject.
State your goal, provide your evidence, and summarize your findings. Write your proofs in complete English sentences, not just phrases thrown together. We expect presentations of proofs similar to those in our texts, including a flush left margin, main equations centered and typically numbered, and additional details. We expect clear, logical thought that progresses, without scattered miscellaneous details which have no bearing, to the solution of the problem. Many classes, beginning with calculus, expect students to write brief paragraph answers to short questions.