© Teacher Created Materials Today’s Lesson Writing Algebraic Expressions

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

© 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, __

© 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

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

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

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

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

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

© 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.

© 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

© 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 t + 5 f – 3 f – t

© 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?

© 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

© 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

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

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

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

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

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

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

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

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