6th Grade Math Textbook, Fundamentals

2-2

Evaluate for a12, b3, and c5.

 Substitute the given values.

 Follow the Order of Operations.

 3

a b

c

15

 5

12  3

 5

a b

c

1 Evaluate 5x^3 y^2 for x2 andy3.

5 x^3 y^2  5 x^3 • y^2

5(2)^3 • (3)^2

5(8) • 9

40 • 9

 360

2

Simplify and Evaluate

Algebraic Expressions

Objective To translate one- and two-step verbal expressions into algebraic expressions

• To evaluate algebraic expressions • To simplify algebraic expressions by combining like terms


• To simplify algebraic expressions by using properties

Elena normally practices on her keyboard for a certain

number of hours each week. In preparation for her concert,

she plans to increase her weekly practice time by 4 hours.

The week before the concert she plans to double that time.

What algebraic expression represents the numbers of hours

she plans to practice the week before her concert?

To write an algebraic expression, choose a variable to

represent the unknown. Then write the algebraic

expression to represent the situation.

Let hthe number of hours Elena normally practices.

double 2 • (h4) increase of 4 hours

So the algebraic expression 2 • (h4) or 2(h4) represents

the number of hours Elena will practice the week before her concert.

If a value of a variable is given, you can evaluatean algebraic expression.

To the algebraic expression, substitute the value given for the

variable and compute according to the order of operations.

If Elena normally practices 5 hours a week, how many hours will she

practice the week before her concert?

2(h4)

2(54) Substitute 5 for h.

2(9)

18

Elena will practice playing on her keyboard for 18 hours

the week before her concert.

Follow the Order of Operations.

Simplify the expression within the parentheses first.

evaluate

 &KDSWHU

Think

5 x^3 5 • x• x• x