1. 1.1 Variables and Expressions
Goals
I can evaluate a variable expression.
I can write variable expressions from word phrases.
I can write a variable expression that models a real life situation.
A.SSE.1.a Interpret parts of an expression such as terms, factors, and coefficients

2. Section 1.1 – Variables and Expressions
Vocabulary:
Variable- a letter or symbol that can be used for a value that can change.
Constant – a number or value that does not change.
Numerical expression – a mathematical phrase that contains only constants and/or operations and NO variables
Algebraic expression – a mathematical phrase that may contain one or more variables, constants, and/or operations

3. We have to be able to “translate” words into expressions
What words indicate a particular operation?
Add Subtract
Sum
Plus
More than
Increase(d) by
Perimeter
Deposit
Gain
Greater than
Up (flights of stairs)
Total
Minus
Take away
Difference
Reduce(d) by
Decrease(d) by
Withdrawal
Less than
Fewer (than)
Loss of

4. We have to be able to “translate” words into expressions
What words indicate a particular operation?
Multiply Divide
Times
Product Of
Twice (×2), double (×2), triple (×3), etc.
Half (×½), Third (×⅓), Quarter (×¼)
Area (by)
Percent (of)
Square (times itself 2 times)
Cube (times itself 3 times)
… to the power of ___
(times itself ___ times)
Split into __ parts
Cost each
Quotient
One-half (÷2), Third (÷3), Quarter (÷4)
Into
Per
Percent (out of 100)

5. 1.1 – Variables and Expressions
Let’s try an example of “translating” a phrase into an algebraic expression:
Nine more than a number y
“more than” means add y 9 ?
Answer: y + 9

6. 1.1 – Variables and Expressions
Let’s try another example of “translating” a phrase into an algebraic expression:
4 less than a number n
“less than” means Subtract 4 ? n
Answer: n – 4.
Why not 4 – n?????

7. 1.1 – Variables and Expressions
Let’s try another example of “translating” a phrase into an algebraic expression:
A number a divided by 12 ? a

8. 1.1 – Variables and Expressions
This one is harder……
5 times the quantity 4 plus a number c

9. 1.1 – Variables and Expressions
John types 62 words per minute. Write an expression for the number of words he types in m minutes.
Joey earns $5 for each car he washes. Write an expression for the number of cars Joey must wash to earn d dollars.

10. 1.1 – Variables and Expressions
We can use an expression to represent a real life situation.
d = rt (Distance traveled equals rate (speed) multiplied by time traveled.)
I=Prt - Simple interest earned by an amount of money P, at an annual rate r, multiplied by the amount of time (t) in years.

11. Example
You plan to ride your bicycle to school and back at an average rate of 6 miles per hour for a distance of 10.5 miles. How long will it take you?

12. Example
Approximately fourteen 20 ounce plastic bottles must be recycled to produce 1 square foot of carpet.
Write an expression for the number of bottles needed to make c square feet of carpet.

13. Assignment
pg. 7 #15-33 odd, 41,43