1.3 variables and expressions 1
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Warm-Up Exercises Lesson 1.3, For use with pages 13- Evaluate the expression. 1. 5 • 6 + 3 • 2 21 (9 – 2) Reminder: You need your math book and calculator in class today!
Transcript of 1.3 variables and expressions 1
Warm-Up Exercises Lesson 1.3, For use with pages 13-18
Evaluate the expression.
1. 5 • 6 + 3 • 2
2. 21 (9 – 2)
Reminder: You need your math book and calculator in class today!
Warm-Up Exercises Lesson 1.3, For use with pages 13-18
Evaluate the expression.
1. 5 • 6 + 3 • 2
ANSWER 36
ANSWER 3
2. 21 (9 – 2)
Reminder: You need your math book and calculator in class today!
Warm-Up Exercises
Lesson 1.3 Variables and Expressions
Day 1
Objective: To be able to write and evaluate variable expressions.
Warm-Up Exercises
• Variable: symbol, usually a letter, that represents one or more numbers.
• Variable Expression: consists of numbers, variables, and operations.
• Algebraic Expression: is one or more algebraic terms in a phrase. It can include variables, constants, and operating symbols, such as plus and minus signs.
For example: 3x2 + 2y + 7xy + 5
Vocabulary
Warm-Up Exercises VocabularyName some synonyms for addition, subtraction, multiplication and division.
Addition Subtraction Multiplication Division
Plus
The sum of
Increased by
Total
More than
Added to
Minus
The difference of
Decreased by
Fewer than
Less than
Subtracted from
Times
The product of
Multiplied by
Of
Twice
Divided by
The quotient of
Separate into equal parts
See page 14 in your textbook.
Warm-Up ExercisesEXAMPLE 3 Translating Verbal Phrases
Verbal Phrase Variable Expression
The sum of a number and 9
The difference of a number and 21
The product of 6 and a number
The quotient of 48 and a number
One third of a number
n + 9
n –21
6n
48n
31 n
Warm-Up ExercisesGUIDED PRACTICE for Examples 2 and 3
Write the phrase as a variable expression using x.
8. a number increased by 15
9. 8 times a number
Verbal Phrase Variable Expression
x + 15
8x
Warm-Up ExercisesGUIDED PRACTICE for Examples 2 and 3
Evaluate the expression when a = 12 and b = 3.
4. 9a
5. ab
Substitute 12 for a= 9(12)
= 108
Substitute 12 for a and 3 for b= (12)(3)
= 36
Multiply.
Multiply.
Warm-Up ExercisesEXAMPLE 2 Evaluating Variable Expressions
Evaluate the expression when x = 8 and y = 2.
a. 3x – 5y 3(8) – 5(2)=
24 – 10=
14=
Substitute 8 for x and 2 for y.
Multiply.
Subtract.
5(8+2)=
50=
Substitute 8 for x and 2 for y.
Add.
b. 5(x + y)
= 5(10)
Multiply.
Warm-Up ExercisesGUIDED PRACTICE for Examples 2 and 3
Evaluate the expression when a = 12 and b = 3.
6. b(a – 6) = 3(12 – 6) Substitute 12 for a and 3 for b
= 3(6) Subtract.
Multiply.= 18
Warm-Up ExercisesGUIDED PRACTICE for Examples 2 and 3
Evaluate the expression when a = 12 and b = 3.
7. 6aa – b
Substitute 12 for a and 3 for b6(12)12 – 3 =
7212 – 3 = Multiply.
9 72= Subtract.
= 8 Divide.
Warm-Up ExercisesDo together: Page 15 #40-43
A. 3.8m
B. 3.8m + 8
C. 27
Warm-Up ExercisesDo together: Page 15 #40-43
30x + 60y – 3z
Warm-Up ExercisesDo together: Page 15 #40-43
13x + 15y + 2z
Warm-Up ExercisesDo together: Page 15 #40-43
Warm-Up ExercisesDo together: Page 15 #40-43
20 – (2.75p + 2.5d) = $1.75
Warm-Up ExercisesHomework
• Page 15 #4-12 even, 13-21 all.– Use Pencil
– Put your name, date, class period and assignment in the right hand corner of your paper.
– Show all your work.
NWEA tomorrow! Meet in the 6th grade computer lab. (by the office)
