Writing Algebraic Writing Algebraic ExpressionsExpressions

Objective:Objective:

Be able to write an algebraic Be able to write an algebraic expression for a word phrase or write a expression for a word phrase or write a

word phrase for an expression.word phrase for an expression.

Warm UpEvaluate each algebraic expression for the

given value of the variables.

1.) 7x + 4 for x = 6

2.) 8y – 22 for y = 9

3.) 12x + for x = 7 and y = 4

4.) y + 3z for y = 5 and z = 6

8y

Warm UpEvaluate each algebraic expression for the

given value of the variables.

1.) 7x + 4 for x = 6

2.) 8y – 22 for y = 9

3.) 12x + for x = 7 and y = 4

4.) y + 3z for y = 5 and z = 6

46

50

868y

23

Although they are closely related, a Great Dane weighs about 40 times as much as a Chihuahua.

When solving real-world problems, you will need to translate words, or verbal expressions, into algebraic expressions.

An expression for the weight of the Great Dane could be 40c, where c is the weight of the Chihuahua.

NotesNotes

In order to translate a word In order to translate a word phrase into an algebraic phrase into an algebraic expression, we must first expression, we must first know some key word know some key word phrases for the basic phrases for the basic operations.operations.

On the back of your notes:On the back of your notes:AdditionAddition SubtractionSubtraction

MultiplicationMultiplication Division Division

Addition Phrases:Addition Phrases:More thanMore than

Increase byIncrease by

Greater thanGreater than

AddAdd

TotalTotal

PlusPlus

SumSum

Subtraction Phrases:Subtraction Phrases:Decreased byDecreased by

Difference betweenDifference between

Take Away Take Away

LessLess

SubtractSubtract

Less than*Less than*

Subtract from*Subtract from*

Multiplication Phrases:Multiplication Phrases:ProductProduct

TimesTimes

Multiply Multiply

OfOf

Twice or doubleTwice or double

TripleTriple

Division Phrases:Division Phrases:QuotientQuotient

DivideDivide

Divided byDivided by

Split equally Split equally

NotesNotesMultiplication expressions should Multiplication expressions should be written in side-by-side form, be written in side-by-side form, with the number always in front of with the number always in front of the variable.the variable.

33aa 2 2tt 1.5 1.5cc 0.4 0.4ff

NotesNotes

Division expressions should Division expressions should be written using the fraction be written using the fraction bar instead of the traditional bar instead of the traditional division sign.division sign.

2

c5

t 3

x

ExamplesExamplesAddition phrasesAddition phrases::

3 more than 3 more than x xx x

the sum of 10 and a number the sum of 10 and a number cc

a number a number nn increased by 4.5 increased by 4.5

ExamplesExamplesAddition phrasesAddition phrases::

3 more than 3 more than x x x+3x+3

the sum of 10 and a number the sum of 10 and a number ccC+10C+10 a number a number nn increased by 4.5 increased by 4.5n + 4.5n + 4.5

ExamplesExamplesSubtraction phrasesSubtraction phrases::

a number a number tt decreased by 4 decreased by 4 the difference between 10 and a the difference between 10 and a

number number yy 6 less than a number 6 less than a number z z

ExamplesExamplesSubtraction phrasesSubtraction phrases::

a number a number tt decreased by 4 decreased by 4t-4t-4 the difference between 10 and a the difference between 10 and a

number number yy10-y10-y 6 less than a number 6 less than a number z z Z-6 Z-6

ExamplesExamplesMultiplication phrasesMultiplication phrases::

the product of 3 and a number the product of 3 and a number tt

twice the number twice the number xx

4.2 times a number 4.2 times a number ee

ExamplesExamplesMultiplication phrasesMultiplication phrases::

the product of 3 and a number the product of 3 and a number tt3t3t twice the number twice the number xx2x2x 4.2 times a number 4.2 times a number ee4.2e4.2e

ExamplesExamplesDivision phrasesDivision phrases::

the quotient of 25 and a number the quotient of 25 and a number bb

the number the number yy divided by 2 divided by 2

2.5 divide 2.5 divide gg

ExamplesExamplesDivision phrasesDivision phrases::

the quotient of 25 and a number the quotient of 25 and a number bb25/b25/b the number the number yy divided by 2 divided by 2y/2y/2 2.5 divide 2.5 divide gg2.5/g2.5/g

ExamplesExamplesconverting f feet into inchesconverting f feet into inches

a car travels at 75 mph for h hoursa car travels at 75 mph for h hours

the area of a rectangle with a length the area of a rectangle with a length

of 10 and a width of wof 10 and a width of w

ExamplesExamplesconverting i inches into feetconverting i inches into feet

the cost for tickets if you purchase 5 the cost for tickets if you purchase 5 adult tickets at x dollars eachadult tickets at x dollars each

the cost for tickets if you purchase 3 the cost for tickets if you purchase 3 children’s tickets at y dollars eachchildren’s tickets at y dollars each

ExamplesExamplesthe total cost for 5 adult tickets and 3 the total cost for 5 adult tickets and 3 children’s tickets using the dollar children’s tickets using the dollar amounts from the previous two amounts from the previous two problems (problems e and f)problems (problems e and f)