Unit 1, Lesson 3
Números primos y números compuestos
Grado 4
Preparation
Lesson Narrative
In previous lessons, students were introduced to the terms “multiples” and “factor pairs.” In this lesson, they learn that whole numbers can be classified as prime or composite based on the number of factor pairs they have.
Students reason about these numbers in terms of the area and pairs of side lengths of rectangles. They learn that a prime number has exactly 1 factor pair—1 and the number itself. A composite number has more than 1 factor pair. They relate “prime” to a number that could represent the area of only one rectangle (with only one pair of side lengths) and “composite” to a number that could represent the area of multiple rectangles (with multiple pairs of side lengths).
Math Community
Tell students that, at the end of the lesson, they will be asked to identify specific actions from their “Doing Math” list they personally experienced.
- Engagement
- MLR8
- Comprehend (in spoken and written language) the meaning of the terms “prime number” and “composite number.”
- Determine the factor pairs of a given whole number 1–100.
- Explain (orally and in writing) strategies for determining whether a given whole number is prime or composite.
Required Preparation
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Create a set of cards from the blackline master for each group of 2.
Teacher Reflection Questions
Which voices went unheard in math class today? How might you leverage each student's ideas and support them being heard and seen in tomorrow's lesson?