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Today’s Lesson. Writing Algebraic Expressions. Warm-Up Activity. Let’s warm up today by finding patterns in numbers. 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, __. Check your answers.
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Today’s Lesson Writing Algebraic Expressions
Warm-Up Activity Let’s warm up today by finding patterns in numbers.
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, __
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
What is the pattern? 3, 6, 9, 12, 15, 18, 21, 24 +3 +3 +3 … +3 each time
What is the pattern? 1, 2, 4, 7, 11, 16, 22, 29 +1 +2 +3 +4 … +1 more each time
What is the pattern? 1, 1, 2, 3, 5, 8, 13, 21 +0 +1 +1 +2 +3 +5 +8 Add the 2 previousnumbers together
Whole-Class Skills Lesson Today we will write algebraic expressions and find patterns in real-life situations to show algebraically.
To review, what does the word variable mean? A variable is an unknown quantity that has the potential to change.
What does the term algebraic expression mean? An algebraic expression is any number sentence using variable(s) and number(s) in any combination.
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
How would you write the following expressions? 8 + 5 A number that is 5 more than 8 t + 5 A number that is 5 more than t f – 3 A number that is 3 less than f f – t A number that is t less than f
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?
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 age Sister’s age
Copy the T-chart below Copy the data for Judy and her sister’s ages. This data comes from the problem. Judy’s age Sister’s age 5 2 8 5 14
Do you see a pattern with Judy and her sister’s ages? Judy’s age Sister’s age 5 2 8 5 14 Judy’s sister’s age is always 3 years less than Judy’s age.
So based on the pattern, when Judy is 14, her sister will be three years less than that—11 years old.
How old will Judy’s sister be when Judy is 20? 20 – 3 = 17 Judy’s sister will be 17.
How old will Judy’s sister be when Judy is 25? 25 – 3 = 22 Judy’s sister will be 22.
Assign a variable to Judy’s age. Judy’s age Sister’s age 5 2 8 5 14 11 j Judy’s age can be represented by a variable, j
What is the best way to figure out Judy’s sister’s age using j as a starting point?
Using j – 3, solve for Judy’s sister’s age when j = 31 31 – 3 = 28 j = 45 45 – 3 = 42