1. Unit 2: One-Variable Equations and Inequalities
Day 1: Writing and simplifying expressions

2. Warm-up
54 ÷ (-9)
7(-4)
6 – (-4)
-4 – (-5)
-5+(-6)

3. Algebraic Expressions
What is a Variable?
A symbol, usually a letter, that represents one or more numbers.
What is an Algebraic Expression?
A mathematical phrase that can include numbers, variables, and operation symbols
Have students take 30 seconds to discuss these questions.

4. Writing Algebraic Expressions
1. Seven more than n
n + 7
2. The difference of n and 7
n - 7
3. The product of seven and n 7n
4. The quotient of n and seven

5. Talk about: 1. Three times a number more than two
2. Three times the quantity of a number and two.
Have groups put their answers either on a white board or come up to the board and record their answers. Talk about the different answers the different groups may have.
3n+2
3(n+2)

6. Talk about: 1. Two less than five times a number
2. Ten less than a number
3. Ten subtracted from a number
Have groups put their answers either on a white board or come up to the board and record their answers. Talk about the different answers the different groups may have.
5n-2
N-10

7. OR Which answer is Correct?
How do we solve algebraic expressions? OR
Which answer is Correct?
5 is the correct answer….We have to follow the law: “Order of Operations!”

8. “Order of Operations!”
P=Parenthesis
E=Exponents
M=Multiplication
D=Division
A=Addition
S=Subtraction
Think of order of operations as putting on socks, shoes, and tying your shoelaces!
Go in order from left to right!!!
Go in order from left to right!!!

9. Exponents?
Exponents are shorthand for multiplication!!! 32 = How can I rewrite 7•7•7•7•7•7

10. What are some equivalent expressions:
Make sure you talk about how to read exponents.

11. Solve the algebraic expressions:
(9 + 4) – ÷ 2 • 7
-8 – – 9 • 2 ÷ 3

12. Classwork
Each pair will create two order of operations questions, one on the front on their card and another on the back side.
Swap cards with another pair and simplify each others’ expressions.
Swap with a third pair and have them check the work, making corrections as needed.
Turn in!

13. Evaluating Expressions
“Evaluate” means solve **To evaluate you will need to substitute (to replace a letter with a number or algebraic expression)

14. 1. Evaluate a2b for a = –2, b = 3
Step 1: Replace the letters with the numbers Step 2: Follow order of operations

15. Evaluate if a = 8, b = -4, and c = -2.
a + b + c 2.
3. 3(b - a) – c b2 – c2

16. Tangram Time! With your partner, complete the tangram activity.
Be sure NOT to write on the tangrams themselves!
Turn in your math / work.

17. Recap:
Write an expression: 3 more than a number doubled.

18. Homework
2.1