Lesson 8

Prime Factors

Est. Class Sessions: 2
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Mathematics Standards

4.NBT.B
Use place value understanding and properties of operations to perform multi-digit arithmetic. (4.NBT.B.5)
4.OA.B
Gain familiarity with factors and multiples. (4.OA.B.4)

Standards for Mathematical Practice

MP1.
Make sense of problems and persevere in solving them.
MP2.
Reason abstractly and quantitatively.
MP8.
Look for and express regularity in repeated reasoning.

Students begin this lesson by writing numbers (with several factors) as a product of at least three factors. Factor trees are then introduced to help students find the prime factorization of the number. To tie together the work they have done so far in the unit, students write and solve number riddles that involve the terms multiple, factor, prime, and square number.

Content in this Lesson

  • Finding all the factors of a number [E3].
  • Finding the prime factorization of a number [E6].
  • Using exponents.
  • Identifying prime numbers [E4].
  • Identifying square numbers [E5].
  • Determining whether one number is a multiple of another [E2].
  • Identifying the important information to solve a problem [MPE1].
  • Showing solution strategy in an organized manner [MPE5].
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Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

 Student Guide  

Teacher Resources

 Teacher Guide - digital    

Supplies for Students

calculator
square-inch tiles
Multiplication Facts I Know chart (Lesson 2 Student Activity Book) Page 39

Materials for the Teacher

Display of Math Practices page (Student Guide) Reference
Unit 3 Assessment Record
Math Facts Class Record

Materials for the Teacher

Make Digit Cards. Make a set of Digit Cards 0–9 using index cards, a deck of playing cards or the Digit Cards 0–9 Masters. If using playing cards, the ace can stand for 1 and a face or joker card can stand for zero. These cards will be used to play a game in DPP item W.

Assessment in this Lesson

Assessment Expectation Assessed
Prime Factors
Check-In: Question 3
Student Guide
Page 99
E6.
Find the prime factorization of a number.
DPP Item Y
Quiz on the Square Numbers
Teacher Guide - digital
E10.
Demonstrate fluency with the multiplication facts for the 5s, 10s, and square numbers.