What's new about prefixes in 4th grade?

Opposite pairs and longer bases. Over- and under- both attach to paid, cooked, and estimate, so students must weigh the sentence's evidence. The in-/im- family (incorrect, impossible, impatient) also arrives, with its spelling quirk of im- before p.

Why is it im-possible but in-complete?

English borrows the rule from Latin: in- shifts to im- before p, b, or m because it's easier to say. Impossible, imbalance, immovable. Kids don't need the history, but noticing the pattern beats memorizing word by word.

4th grade prefixes

4th grade prefixes worksheets

By 4th grade the set expands to non-, over-, under-, in-, and im-, and the bases get longer: incomplete, overestimate, indecipherable. The skill matures from memorizing prefixes to weighing which one the sentence actually needs.

Free printable PDF worksheet, aligned to Common Core L.4.4.b.

Each print is a different sheet with its own answer key. You don't need to sign up.

The kind of sentences you'll get

Circle the letter of the word with the correct prefix.

The mayor will the fixed playground on Monday. disopen · unopen · reopen
Answer: reopen
I and missed the bus. overslept · unslept · reslept
The trail made us check the map twice. unfamiliar · refamiliar · disfamiliar

Every print pulls a new set of sentences at this level, so a make-up test or a second sibling gets a different mix.

What's on a 4th grade sheet

4th grade sheets draw from 60 sentences, 10 to a page. All 60 are on 3rd grade sheets too, along with 60 more.

Some of the answers:

nonpermanentimpossibleincorrectimpatientindoorunstableunreadablemisunderstoodimpassableunprepared

Choose the word. Circle the letter of the word with the correct prefix. 10 questions per page.

Every version prints on US Letter or A4, with its answer key on the last page.

How to teach this

Push into contrast pairs: overpaid against underpaid, overcooked against undercooked. When two opposite prefixes both make real words, the answer lives entirely in context clues, which is the reading skill the standard is really after. Invite skepticism, too: ask whether uncle, under, or invent actually contain prefixes.

Watch for: A prefix changes meaning, not spelling: the base word keeps all its letters (re + read = reread). Not every word that starts with those letters has a prefix. Uncle isn't un + cle.

Common questions about 4th grade prefixes

What's new about prefixes in 4th grade?: Opposite pairs and longer bases. Over- and under- both attach to paid, cooked, and estimate, so students must weigh the sentence's evidence. The in-/im- family (incorrect, impossible, impatient) also arrives, with its spelling quirk of im- before p.
Why is it im-possible but in-complete?: English borrows the rule from Latin: in- shifts to im- before p, b, or m because it's easier to say. Impossible, imbalance, immovable. Kids don't need the history, but noticing the pattern beats memorizing word by word.

Related worksheets

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Aligned to Common Core L.4.4.b. Reviewed by the One more sheet team. Content version 241, updated October 2026.

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