No hyphen generally as a prefix: noncredit, nondegree, etc. Exceptions: non- with a proper adjective or a capitalized word like non-high-school graduate, non-Germanic, etc.
Spell out numbers 1 through 10; use figures for numbers above 10.
Use a comma with numerals of 1,000 and above (except dates – 2021).
Exceptions to the rules: ages, numbers with percent signs and dollar signs, votes, scores, temperatures, odds, decimals, TV channels, department numbers, course numbers, section numbers, room numbers, street addresses, dimensions, page numbers.
Use the same style to express related number above and below 10. If any of the numbers are above 10, put them all in figures.