Warm Up: Use Chunking and Order of Operations to solve.

1)

2)

3)

4)

( )4 3 6 2 10

24 2 18 5 1 [ ( )]

50 36 4 5

8 5 4

10 6

Learning Target Read Learning Target #2. Evaluating Algebraic Expression Problems

are like this: Evaluate if x = 2 and y = 4

Rate your self in the “B” (before) section for LT #2 on how well you can do problems like these.

23 yx

Evaluating Algebraic

Expressions

ExpressionsAn expression is NOT an equation because it DOES NOT have an equalsign. There are 2 types of expressions.

5 + 84 Numerical3x + 10 Algebraic

Notice there are no equal signs in these Expression (so they are not equations!)

Numerical ExpressionA numerical expression containsonly numbers and symbols.

(5 3) + 8

Algebraic ExpressionAn algebraic expression contains only numbers, symbols, and variables. It is sometimes referred to as a variable expression.

The product of 3 and x 3xThe sum of m and 8 m + 8The difference of r and 2 r - 2

What is a variable?A variable represents an unknown value.

1) 3 + ___ = 11

2) 6 + = 8

3) 8 + x = 10

4) 5 + = 9

These are all variables

Variable Expressions

Example Meaning Operation

7x 7 times x multiplicationw

10w divided by 10 division

8 p 8 plus p addition

k 5 k minus 5 subtraction

Variable expressions consist of constants,variables, and operations.

Evaluate Evaluate means to find the value of an

algebraic expression by substituting numbers in for variables.

m = 28 + m ?8 + 2 10

Variable SubstitutionEvaluate the variable expression when n = 6.

1) n 8 2) n 26 8

14

6 24

Substitute. Chunk. Use OOO and PEMDAS to complete

Do on whiteboards!

Variable SubstitutionEvaluate the variable expression when n = 6.

3) 3n 4) n6

3 6

1866

1

Substitute. Chunk. Use OOO and PEMDAS to complete

Variable SubstitutionEvaluate the variable expression if a = 3 and b = 4.

1) 6a b 2) a 2b6 43

18 414

3 42 3 8

11

Substitute. Chunk. Use OOO and PEMDAS to complete

Variable SubstitutionEvaluate the variable expression if a = 3 and b = 4.

5) 6ba

6) 5b a

63

4

243

8

5 34

20 3

17

Variable SubstitutionEvaluate the expression if x = 3 and y = 4.

1) 2)2 2x y 26 x y 1 2 23 4

9 16

25

26 (3 14 ) 26 3(5)26 15

11

Take Out Your Learning Targets!!!

An expression is NOT an equation because it does not have an equal sign.

NUMERICAL EXPRESSION: Contains only numbers and symbols. Example: 5 3 + 4

ALGEBRAIC EXPRESSION: Contains numbers, symbols, and variables. Example: m + 8

A VARIABLE is a letter or symbol that represents a number. Example: x

TYPES OF EXPRESSIONS LT #2

Example Problem: Evaluate

4x – 5 + 2(y – 3)

Show the substitution4(2) – 5 + 2(4 – 3)

Chunk it4(2) – 5 + 2(4 – 3)

When x = 2 and y = 4

5 Work down. No equal signs.

8 – 5 + 2(1) Work within each chunk.

3 + 2 Add/Subtract chunks from left to right.

8 – 5 + __2___ Work within each chunk.

LT #2