Some good proofreading exercises from free worksheets include correcting the errors in a list of misspelled words, identifying sentences with correct punctuation and rewriting sentences to eliminate grammar errors. Free worksheets that cover these topics are available online from websites such as EnglishForEveryone.com and K12Reader.com.
EnglishForEveryone.com offers dozens of worksheets that feature proofreading exercises as of 2015. Students must demonstrate knowledge of spelling, syntax, punctuation and proper verb tense. Each worksheet gives an example passage with highlighted phrases. Proofreading students must choose the correct phrasing from a list of multiple choices. The worksheets are suitable for all ages.
K12Reader.com offers worksheets for use by students at specific grade levels. The exercises cover tasks including spelling correction and rewriting complete paragraphs.