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)