Course 3
1-2 Algebraic Expressions
Course 1
1-2 Algebraic Expressions
Course 3
Warm UpWarm Up
Problem of the DayProblem of the Day
Lesson PresentationLesson Presentation
Course 3
1-2 Algebraic Expressions
Warm UpEvaluate each expression for the given values of the variables.
Which operation symbol goes with each word?
2318
1
+
4. Sum
5. Product
6. Quotient7. Difference
1. 9y 13 for y = 42. 6n + 2p for n = 2 and p = 3
3. 3x y for x = 1 and y = 2
Course 3
1-2 Algebraic Expressions
Problem of the Day
Find a pair of numbers that fits the description. Their product is 221 and their sum is 30.
13, 17
Course 3
1-2 Algebraic Expressions
Learn to translate between algebraic expressions and word phrases.
Course 3
1-2 Algebraic Expressions
• a number plus 5• add 5 to a number• sum of a number and 5• 5 more than a number• a number increased by 5• a number minus 11• subtract 11 from a number• difference of a number and 11• 11 less than a number• a number decreased by 11
• 3 times a number• 3 multiplied by a number• product of 3 and a number
• a number divided by 7• 7 divided into a number• quotient of a number and 7
++
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Word Phrases Expression
n + 5
x 11
3m
or a 7a7
Course 3
1-2 Algebraic Expressions
Write an algebraic expression for each word phrase.
Additional Examples 1: Translating Word Phrases into Math Expressions
A. 9 less than a number w 9 less than a number ww – 9w – 9
B. 3 increased by the difference of p and 53 increased by the difference of p and 53 + (p – 5)3 + p – 5
Course 3
1-2 Algebraic Expressions
Write an algebraic expression for each word phrase.
Check It Out: Example 1
A. the sum of a number h and 88 minus 4 the sum of h and 88 minus 4h + 88 – 4h + 88 – 4
B. the quotient of a number f and 6quotient of f and 6f 6
f6
Course 3
1-2 Algebraic Expressions
Write a word phrase for the algebraic expression 9 – 3c.
Additional Example 2: Translating Math Expressions into Word Phrases
9 – 3c
9 – 3 • c
9 minus the product of 3 and c
9 minus the product of 3 and c.
Course 3
1-2 Algebraic Expressions
Check It Out: Example 2
Write a word phrase for the algebraic expression 7 + 19b.
7 + 19b
7 + 19 • b
7 plus the product of 19 and b
7 plus the product of 19 and b.
Course 3
1-2 Algebraic Expressions
To solve a word problem, you must first interpret the action you need to perform and then choose the correct operation for that action.
Separate into equal groups
Multiply
How many more? How many less?
Combine
Combine equal groups
Separate
Add
Subtract
Divide
Action Operation Possible Question Clues
How many all together?
How many all together?
How many equal groups?
Course 3
1-2 Algebraic Expressions
A restaurant leased its banquet hall for a function. The cost was $10 per person. Write an algebraic expression to evaluate what the cost would be if 20, 21, 22, or 23 people attended the function
Additional Example 3: Writing and Evaluating Expressions in Word Problems
$10 dollars • n Combine n equal amounts of $10. $10n In dollars
20 $10 • 20 $20021 $10 • 21 $21022 $10 • 22 $22023 $10 • 23 $230
n $10 • n CostEvaluate for n = 20, 21, 22, and 23.
Course 3
1-2 Algebraic Expressions
Gasoline costs $1.99 per n gallons. What will the cost be for 10, 12, 14, and 15 gallons?
Check It Out: Example 3
$1.99 • n Combine n equal amounts of $1.99. $1.99n In dollars
10 $1.99 • 10 $19.9012 $1.99 • 12 $23.8814 $1.99 • 14 $27.8615 $1.99 • 15 $29.85
n $1.99 • n Cost
Evaluate for n = 10, 12, 14, and 15.
Course 3
1-2 Algebraic Expressions
Write a word problem that can be evaluated by the algebraic expression 27 + t, and evaluate the expression for t = 1.76.
Additional Example 4: Writing a Word Problem from a Math Expression
Possible Answer:
Amed bought a new sweater for $27 plus sales tax t. If the tax was $1.76, what was the total cost of the sweater?
27 + t
27 + 1.76 = 28.76 Substitute 1.76 for t.
The total cost of the sweater was $28.76.
Course 3
1-2 Algebraic Expressions
Write a word problem that can be evaluated by the algebraic expression 43 - d, and evaluate the expression for d = 10.24.
Check It Out: Example 4
Possible Answer: Tina bought a new jacket for $43 minus a store credit. If the store credit was $10.24 , what was the total cost of the jacket?
43 + d
43 – 10.24 = 33.24 Substitute 10.24 for t.
The total cost of the jacket was $33.24.
Course 3
1-2 Algebraic Expressions
Lesson Quiz
Write an algebraic expression for each word phrase.
1. 5 less than a number k
2. a number x divided by 11
3. 4 times the sum of n and 5
Write an algebraic expression to evaluate the word problem.
4. Karen buys n raffle tickets for $0.50 each. If she buys 13 of them, how much will they cost?
k – 5
4(n + 5)
0.50n; $6.50
x11