Fourth graders learn that a prime number has exactly two factors while a composite number has more, and sort numbers into the two groups by finding their factors.
Students will be able to…
Some numbers can be split into equal groups many ways, and some refuse to split at all. What makes a number prime, and how can you tell?
Project this and sort each number into prime or composite — tap a number, then tap which group it belongs in.
Tap any phase to open the teacher moves and student actions.
Some numbers of tiles make only one rectangle; others make several. Why?
Students sort numbers into prime and composite.
Students list factors to decide.
Students classify a set of numbers.
Students reflect on the rule.
Aligned to the Common Core State Standards for Mathematics (Grade 4).
Find all factor pairs for a whole number 1-100; determine whether a number is prime or composite.
Find the greatest common factor of two whole numbers.
Look for and make use of structure in factor patterns.
Construct viable arguments and critique the reasoning of others.
Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.
Have students pick numbers up to 30, list the factors of each, and label it prime (exactly two factors) or composite (more than two). A printable prime-and-composite worksheet is in the Mathematics library.
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A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.