1. + Grade 5 Lesson 1.9 Factor strings and prime factorizations

2. + Math Message 8 + 8 and 4 * 4 are two names for the number 16. On a sticky note, write at least five other names for 16. Put this on your number when you are done. These are called Name –Collections for 16.

3. + Factor Strings A factor string is a multiplication expression that has at least two factors that are greater than 1. In a factor string, the number 1 cannot be used as a factor. For example, the factor string for 24 is 2 * 3 * 4 The length of this factor string is 3 (we count the number of factors in it) The commutative property of multiplication (4 * 2 is the same as 2 * 4) applies here too. Therefore 2 * 3 * 4 is the same as 3 * 4 * 2 and is considered the same string.

4. + You try Find the factor strings for the following numbers: 7What is the answer to this one 1 * 7 Can 7 have a factor string? No… Why not? Because prime numbers do not have factor strings. 30 50 54 72

5. + Prime Factorization The longest factor string for a number is called Prime factorization. For example, the prime factorization for 24 is 2 * 2 * 2 * 3

6. + Workbook pages 25 and 26 You may work with a partner if you wish. Complete workbook pages 25 and 26. Ask for help if it is needed.

7. + Using Factor Trees to find prime factorization (page 25) 36 6 * 6 3 * 2 * 3 * 2 36 3 * 12 3 * 3 * 4 3 * 3 * 2 * 2

8. + Name that Number Game Pick a partner and Play Name that Number, practicing applying number properties, equivalent names, arithmetic operations, and basic facts.

9. + Homework Page 24 is homework for this lesson.

10. + Enrichment Exploring Palindromic Squares Page 28 Explore the relationships between numbers and their squares, find palindrome numbers by looking at the arrangement of their digits. List 3 and 4 digit palindromes, then square these to find palindromic squares – (the square of a palindrome number is also a palindrome number!)