1. CHAPTER 1 1-1 VARIABLES AND EXPRESSIONS

2. WARM -UP Add or subtract Multiply or divide -12+(-5) 5. -13*5
-12+(-5) *5
2. 9-(-4) −600÷12
3. 5+(-7) *0.3
4. -8+(10) (880)

3. Warm –up answers Add or subtract Multiply or divide
-12+(-5) *5 -65
2. 9-(-4) −600÷12 -50
3. 5+(-7) *
4. -8+(10) (880) 660

4. Variables and expressions
Objectives:
Translate between words and algebraic expressions
Evaluate algebraic expressions

5. Variables and expressions vocabulary
variable: is a letter or symbol used to represent a value that can change.
Constant: is a value that does not change.
Numerical expression: may contain only constants and/or operations.
Algebraic expression: may contain variables, constants and/or operations.

6. Variables and expressions vocabulary examples
Give examples for the following:
Variables :
Constants:
Algebraic Expressions:

7. Variables and expressions Diagram
Use diagram to help translate algebraic expressions to words +
Plus, sum , increased by , more than __
Minus, difference, less than *
Times, product ,equal group of, multiply by ÷
Divided by, quotient

8. Variables and Expressions Translate from algebraic expression to words
I. Give different ways to write each algebraic expression into words
Example 1:
x+5
The sum of x and 5
Five more than x
X plus 5
X increased by 5

9. Translate from algebraic expressions to words
B) m-6
The difference of m and 6
6 less than m
m minus 6
C) 3*k
The product of 3 and k
3 times k

10. Translate from algebraic expressions to words
D) g÷8
g divided y 8
The quotient of g and 8

11. Translate from algebraic expressions to words
Student practice :
Check it out 1a to 1d
1a. 4-n c. 9+q
1b. 𝑡 d. 3(h)

12. Variables and expressions Diagram
Use to help you translate words into algebraic expressions
Add
Put together, combine
Subtract
Find how much more or less
Multiply
Put together equal groups
divide
Separate into equal group

13. Translate words into algebraic expressions
Example 2:
Evelyn has 2 more years than her sister Adriana. Write and expression for Evelyn’s age.
* a+2
B) Sam is 3 years younger than sue, who is y years old. Write an expession for sam’s age.
* y-3

14. Translate words into algebraic expressions
Words to look for that will help you with translation
addition
sum , more
Subtraction
Less, difference, minus
Multiplication
Per, times, product
Division
Quotient, ratio

15. Translating words into algebraic expressions
C) Mario’s car is going 55 miles per hour. Write an expressions for how fast is Mario’s car going.
55 h
William runs a mile in 15 minutes. Write a an expression for the number of miles that william run in m minutes.
* 𝑚 15
Student Practice : check it out 2a-2c

16. Evaluating Algebraic Expressions
Evaluate: is to find its value.
Substitute: to replace
To evaluate an algebraic expression substitute the variables in the expression for numbers and then simplify as needed.
Hint: Usually they give the numbers you need to substitute the variables for.

17. Evaluating Algebraic Expressions
Example 3:
Evaluate each expression for x=8 , y=2 and z=4
x+z
x+z= * substitute x with 8 and z with 4
= 8+4= simplify

18. Evaluating Algebraic Expressions
B) xyz
xyz = 8*2*4 substitute x,y and z with 8,2 and 4
= 8*(2*4)=8*8 simplify
= 64
𝑥𝑦 𝑧
𝑥𝑦 𝑧 = 8∗ substitute
= 16 4 = simplify

19. Student Practice
Evaluate the following expressions give x=3,y=-7 and z=5
A) xy
B) 2x+y
C) x-z-y
* Check it out 3a-5

20. Evaluating Algebraic Expressions
Example 4: Challenge
Example 5:
Comparing cellphones plans
*Lets says company AC has a plan that consists of $35 plan fee for the first 600 minutes plus 10 cents per minute pass the 600 minutes.
Company BC has a plan that consists of $25 plan fee for the first 600 minutes plus 25 cents per minute pass the 600 minutes.
which plan is less expensive for 800 minutes?

21. Variables and Expressions
Homework for lesson 1-1
Page 9 and 10
17-35 evens,41

22. closure
Today we learned about what are variables, translating algebraic expressions into words and vice versa.
We also learned about evaluating algebraic expressions.
Tomorrow we are going to learn chapter 1-2 solving equations by adding or substracting