Virginia SOL 5.NS.2

5.NS.2 is a Standards of Learning standard. These are the knowledge and skills expectations under it.

• 5.NS.2.a

  Given a whole number up to 100, create a concrete or pictorial representation to demonstrate whether the number is prime or composite, and justify reasoning.

• 5.NS.2.b

  Classify, compare, and contrast whole numbers up to 100 using the characteristics prime and composite.

• 5.NS.2.c

  Determine the prime factorization for a whole number up to 100.

01

What Students Need to Do

Students use factor pairs, arrays, or drawings to decide whether a number is prime, composite, or neither. They explain the classification and write composite numbers as products of prime factors.

02

What Mastery Looks Like

A student can list all factor pairs and use them to classify a number, including recognizing that 1 is neither prime nor composite. They can complete a factor tree and write the result using only prime factors.

03

Common Misconceptions

Students may call 1 prime because it has one factor, but prime numbers have exactly two factors. They may assume every odd number is prime. Some stop a factor tree before every factor is prime or think different trees produce different answers.

04

How to Assess It

Exit ticket: For 31 and 84, list the factor pairs, classify each number, and explain each choice. Write the prime factorization of 84.

1. 01

   Give pairs counters and number cards 1, 17, 24, and 49; they build every possible array and label each number.

2. 02

   Ask students to write: “Why is 2 the only even prime, and why is 1 neither prime nor composite?”

3. 03

   Play Factor Tree Match: students pair number cards with prime factorization cards, then check each match by multiplying the factors.

4. 04

   Plan seating for 29 and 30 guests; students find equal-row arrangements and explain which group size offers more layout choices.

• 3.NS.2

  The student will demonstrate an understanding of the base 10 system to compare and order whole numbers up to 9,999.

• 2.NS.2

  The student will demonstrate an understanding of the ten-to-one relationships of the base 10 number system to represent, compare, and order whole numbers up to ...