1. © Teacher Created Materials Today’s Lesson Writing Algebraic Expressions

2. © Teacher Created Materials Let’s warm up today by finding patterns in numbers. Warm-Up Activity

3. © Teacher Created Materials Find the missing numbers in the following patterns. 3, 6, 9, __, 15, 18, __, 24 1, 2, 4, __, 11, 16, __, 29 1, 1, 2, 3, 5, __, 13, __

4. © Teacher Created Materials Check your answers. 3, 6, 9, 12, 15, 18, 21, 24 1, 2, 4, 7, 11, 16, 22, 29 1, 1, 2, 3, 5, 8, 13, 21

5. © Teacher Created Materials What is the pattern? 3, 6, 9, 12, 15, 18, 21, 24 +3 each time +3 +3 +3 …

6. © Teacher Created Materials What is the pattern? +1 more each time +1 +2 +3 +4 … 1, 2, 4, 7, 11, 16, 22, 29

7. © Teacher Created Materials What is the pattern? Add the 2 previous numbers together +0 +1 +1 +2 +3 +5 +8 1, 1, 2, 3, 5, 8, 13, 21

8. © Teacher Created Materials Today we will write algebraic expressions and find patterns in real-life situations to show algebraically. Whole-Class Skills Lesson

9. © Teacher Created Materials To review, what does the word variable mean? A variable is an unknown quantity that has the potential to change.

10. © Teacher Created Materials What does the term algebraic expression mean? An algebraic expression is any number sentence using variable(s) and number(s) in any combination.

11. © Teacher Created Materials How would you write the following expressions? A number that is 5 more than 8 A number that is 5 more than t A number that is 3 less than f A number that is t less than f

12. © Teacher Created Materials How would you write the following expressions? A number that is 5 more than 8 A number that is 5 more than t A number that is 3 less than f A number that is t less than f 8 + 5 t + 5 f – 3 f – t

13. © Teacher Created Materials Judy and her sister are born in the same month, but in different years. Judy is 5 years old and her sister is 2. When Judy turns 8, her sister will be 5. How old will Judy’s sister be when Judy is 14?

14. © Teacher Created Materials How did you solve that problem? Just one of the ways to solve this problem is to make a T-chart. This is a T-chart. Judy’s ageSister’s age

15. © Teacher Created Materials Copy the T-chart below Copy the data for Judy and her sister’s ages. This data comes from the problem. Judy’s ageSister’s age 52 85 14

16. © Teacher Created Materials Do you see a pattern with Judy and her sister’s ages? Judy’s ageSister’s age 52 85 14 Judy’s sister’s age is always 3 years less than Judy’s age.

17. © Teacher Created Materials So based on the pattern, when Judy is 14, her sister will be three years less than that—11 years old.

18. © Teacher Created Materials How old will Judy’s sister be when Judy is 20? 20 – 3 = 17 Judy’s sister will be 17.

19. © Teacher Created Materials How old will Judy’s sister be when Judy is 25? 25 – 3 = 22 Judy’s sister will be 22.

20. © Teacher Created Materials Assign a variable to Judy’s age. Judy’s ageSister’s age 52 85 14 Judy’s age can be represented by a variable, j j 11

21. © Teacher Created Materials What is the best way to figure out Judy’s sister’s age using j as a starting point?

22. © Teacher Created Materials We can write an algebraic for Judy’s sister’s age. j – 3

23. © Teacher Created Materials Using j – 3, solve for Judy’s sister’s age when j = 31 31 – 3 = 28 j = 45 45 – 3 = 42