This worksheet helps students practice adding the prefixes dis-, non-, and un- to base words to change their meaning.

A. Add the correct prefix to the front of each base word to make a new word.
1. unzip
2. dishonest
3. fat → (no common prefix from dis-, non-, un- makes a standard word; likely intended as "unfat" is not standard, so perhaps "nonfat" is acceptable)
4. disagree
5. unripe
6. unpleasant
7. nonstop
8. disrespect
9. unfair
10. disobey

B. Use the words you made above to complete each sentence.
1. Haley knew it was dishonest to copy her sister's homework.
2. Luke could not unzip his jacket.
3. Claire ate some nonfat yogurt before going for a run.
4. Gloria did not tolerate disrespect from anyone.
5. Phil worked nonstop on his project.
6. Cameron and Mitchell disagree about everything.
7. Jay had an unpleasant time at the party.
8. Manny would never disobey his mother.
9. Uy ate the banana even though it was still unripe.
10. Alex felt her teacher was being unfair.