Download 1.3 Write Expressions

Name: _______________________________________________
Date: _________________
Algebra 1
1.3 Write Expressions
Vocabulary
•
•
•
Verbal Model — a real life situation using words as labels and using math symbols to relate the words
Rate — a fraction that compares two quantities measured in different units
Unit Rate — when the denominator of a rate is one
An algebraic expression contains: one or more numbers or variables and one or more arithmetic operations
Examples:
x–3
3 • 2n
4
1
m
In expressions, there are many different ways to write multiplication
1)
ab
2) a • b
3) a(b) or (a)b
4) (a)(b)
5) a x b
Division, on the other hand, is written as:
1) x/3
2) x ÷ 3
Throughout this year, you will hear many words that mean addition, subtraction, multiplication, and division. Complete the table
with as many as you know:
Addition
Subtraction Multiplication Division
A. Translating Verbal Phrases
Examples:
 4 less than the quantity 6 times a number n
 3 times the sum of 7 and a number y
 The difference of 22 and the square of a number m
Now Try This One:
 The quotient when the quantity 10 plus a number x is divided by 2:
GUIDED PRACTICE:
Write an algebraic expression for:
1. m increased by 5:
2. 7 times the product of x and t:
3. 11 less than 4 times a number:
4. two more than 6 times a number:
5. the quotient of a number and 12:
6. Which of the following expressions represents 7 times a number decreased by 13?
1.
7x + 13
2. 7x - 13
3. 13 - 7x
4. 13 + 7x
7. Which one of the following expressions represents 28 less than three times a number?
1.
28 - 3x
2. 3x – 28
3. 28 + 3x
4. 3x + 28
B. Write a verbal expression for:
m
.
2) r
1) 8 + a.
GUIDED PRACTICE:
1.
Which of the following verbal expressions represents 2x + 9?
1.
9 increased by twice a number
3. twice a number decreased by 9
2. a number increased by nine
4. 9 less than twice a number
2. Which of the following expressions represents the sum of 16 and five times a number?
1.
5x - 16
2. 16x + 5
3.16 + 5x
4. 16 - 5x
3. Which of the following verbal expressions represents x2 + 2x?
1.
the sum of a number squared and twice a number
2. the sum of a number and twice the number
3.
twice a number less than the number squared
4. the sum of a number and twice the number squared
4. Which of the following expressions represents four less than the cube of a number?
1.
4 – x3
2. 4 – 3x
4. x3 – 4
3. 3x – 4
C. Write an expression
You have a ribbon that is 8 inches long
1.
2.
Suppose you cut a 2in piece? What would you do to find the remaining length??
Suppose you cut a piece n inches? How could you write an expression of the length remaining??
D. Find a Unit Rate
A car travels 110 miles in 2 hours. Find the Unit Rate.
E. Solve a Multi Step Problem
Your basic monthly charge for cell phone service is $30, which includes 300 free minutes. You pay a fee for each extra
minute you use. One month you paid $3.75 for 15 extra minutes. Final your total bill if you use 22 extra minutes.