Maryland Math 4.NOS.C.8.d

Math4th GradeNumber and Operation Sense

The Standard

4.NOS.C.8: Explain and apply concepts of factors, multiples, and prime and composite numbers for whole numbers in the range of 1-100.

Determine whether a given whole number in the range of 1–100 is prime, composite, or neither.

Maryland College and Career Ready Standards for Mathematics (2025) · GAIN FAMILIARITY WITH FACTORS AND MULTIPLES.

Teacher's field guide

What Students Need to Do: Students find factor pairs for numbers up to 100. They count the different factors and sort each number as prime, composite, or neither.
What Mastery Looks Like: A student lists all the factors of a number without missing a pair. They explain why 1 is neither and why 2 is prime, even though it is even.
Common Misconceptions: Some students call 1 prime because it has no other factors. Others call 9 prime because it is odd, or 2 composite because it is even.
How to Assess It: Exit ticket: Classify 1, 2, 9, and 17 as prime, composite, or neither. List the factors that support each answer.

Lesson moves

Give pairs bags of 1, 2, 9, and 17 square tiles; have them build rectangular arrays and label each number.
Ask, 'Is every odd number prime?' Have students write an answer using 7 and 9 as evidence.
Play factor card sort: students draw number cards, list factor pairs, then place each card in a prime, composite, or neither pile.
Plan equal rows of seats for 23 and 24 students; compare the possible arrangements and label each class size.

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