What's the plural of moose?

Moose. It joins sheep and deer in the unchanging group, and no, meese has never been a word, however satisfying it would be. These no-change plurals make good challenge items because the tempting wrong answer sounds so plausible.

People, in nearly all writing a 4th grader will do. Persons survives in legal and technical phrases (missing persons), which is worth mentioning exactly once as trivia. Our items treat people as the correct plural of person.

4th grade irregular plural nouns

4th grade irregular plural nouns worksheets

By 4th grade, the set widens to the odd corners: oxen, people, moose, and the f-to-ves crossovers like wolves and knives. Students also meet words where two forms exist, learning that "irregular" doesn't mean lawless.

Free printable PDF worksheet, aligned to Common Core L.3.1.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 fix

Write the plural of the word in parentheses to complete each sentence.

The dentist counted twenty of Maya’s (tooth) at her checkup.
Fixed: The dentist counted twenty of Maya’s teeth at her checkup.
Thousands of (person) filled the stadium for the final.
At night, two (wolf) howled from the ridge.

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, 8 to a page. 39 of the 60 aren't on 3rd grade sheets. The other 21 are.

A few of the sentences, as the answer key corrects them:

At the county fair, nine prize sheep waited to be judged.
For the ecosystem project, we charted how many fish swim past the dock each week.
My report explains why gray wolves were returned to the national park.

Fix it. Write the plural of the word in parentheses to complete each sentence. 8 sentences to fix per page.
Choose the word. Circle the letter of the correct plural. 10 questions per page.

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

How to teach this

The interesting conversations at this level are the edge cases. People versus persons, fish versus fishes, and the -ves family all reward a minute of discussion about how dictionaries record what speakers actually do. If a student asks why English works this way, the honest answer, that the language kept its oldest words' oldest habits, tends to satisfy.

Watch for: Some plurals don't change at all: one sheep, five sheep; one deer, three deer. The number word does all the work. Double-marked forms like mices or feets are never right; the changed word is already plural.

Common questions about 4th grade irregular plural nouns

What's the plural of moose?: Moose. It joins sheep and deer in the unchanging group, and no, meese has never been a word, however satisfying it would be. These no-change plurals make good challenge items because the tempting wrong answer sounds so plausible.
People or persons?: People, in nearly all writing a 4th grader will do. Persons survives in legal and technical phrases (missing persons), which is worth mentioning exactly once as trivia. Our items treat people as the correct plural of person.

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Aligned to Common Core L.3.1.b. Reviewed by the One more sheet team. Content version 241, updated October 2026.

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