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Campus: Harper
Author(s): Jennifer Black
Date Created / Revised: 10/31/13
Six Weeks Period: 2nd
Grade Level & Course: Fifth Grade Math
Timeline: 3 days
Unit Title: Factors and Primes
Stated Objectives:
TEK # and SE
Lesson # 1
5.3D Identify common factors of a set of whole numbers.
5.5B Identify prime and composite numbers using concrete objects, pictorial models, and
patterns in factor pairs.
5.14C Select or develop an appropriate problem-solving plan or strategy, including drawing a
picture, looking for a pattern, systematic guessing and checking, acting it out, making a table,
working a simpler problem, or working backwards to solve a problem.
5.14D Use tools such as real objects, manipulatives, and technology to solve problems.
5.15A Explain and record observations using objects, words, pictures, numbers, and technology.
5.15B Relate informal language to mathematical language and symbols.
5.16A Make generalizations from patterns or sets of examples and nonexamples.
5.16B Justify why an answer is reasonable and explain the solution process.
See Instructional Focus Document (IFD) for TEK Specificity
Key
Understandings
Misconceptions
When a counting number can be described by several factor pairs, then it is composite; when a
counting number can be described with only by one factor pair, then it is prime.
The numbers 0 and 1 are considered neither prime nor composite since there are an infinite
number of factor pairs that have the product of 0 and 1 has only one factor pair – itself.
Prime and composite numbers can be even or odd.
Factors can be expressed as either prime or composite numbers.
Generalizations about whether a number is prime or composite can be made and justified by
using concrete objects, pictorial models, patterns in factor pairs and verbal descriptions.
A variety of problem solving strategies can be used to find the factors, both prime and/or
composite, of a set of whole numbers.
A set of whole numbers can be described by its factors and common factors.
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Some students may think that there is only one way to represent factor pairs. Factor
pairs can be represented multiple ways: factors pairs of 12 are (1,12), (2,6), (3,4), list of
factors: (1,2, 3, 4, 6, 12), multiplication (1 x 12, 2 x 6, 3 x 4), factored tree pairs
(
), and/or T-charts or tables.
Some students may think that 0 and 1 are prime numbers.
Some students may think that all odd numbers are prime numbers.
Some students may think that if two numbers have a factor in common, then that is the
only factor they have in common. That may be true for some numbers but not all. When
finding common factors of two numbers, students need to complete the list of factors for
each number and then find all common factors.
Key Vocabulary
Common factor(s)
Composite number
Divisibility
Factor
Prime number
Suggested Day
5E Model
Instructional Procedures
Day 1- Engage
Write the numbers 2, 3, 4, 5, 10, 11, 14, 15, 17, and 24 on the
board. Tell the students to sort them on a T-chart, but don’t tell
them how to classify them. Discuss all the ways they could have
classified them (odd/even, prime/composite, single digit/double
digit, etc.)
Explore
Review what the students already know by having them complete
Motivation Math pg. 97 in pairs.
Day 2 –Explain
Review what a factor is. Show that there are several ways to find
the factors of a number: i.e. T-Chart, rainbow method, etc.
Find the factors of 2, 3, 5, 10, 14, and 24. Ask the students if any
of them have something in common (some only have 2 factors.)
Do any numbers have common factors?
Explain the difference between prime and composite. (0 and 1
are neither prime nor composite.) Teach Motivation Math pg. 98
Extend
Have students choose one of the following numbers to create a
factor tree (2, 3, 10, 36, 24, and 40). Tell them to write the prime
factorization of that number and decide if it is prime or composite.
Day 3 –Evaluate
Motivation Math Pg. 99-100
Accommodations
for Special
Populations
Accommodations for instruction will be provided as stated on each student’s (IEP)
Individual Education Plan for special education, 504, at risk, and ESL/Bilingual.
Materials, Resources, Notes
(Engage, Explore, Explain, Extend/Elaborate, Evaluate)
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Motivation Math pg.
97
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Motivation Math pg.
98
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Motivation Math pg.
99-100