Writing expressions, equations, and inequalities from word problems

1
Writing expressions, equations, and inequalities
from word problems

• Lets review our Vocabulary!
• Please write all the following vocabulary words
  in your Math Journal for future use.

Slide 1
2
Essential Vocabulary

• Difference means subtraction
• The difference between my age and my younger
  brothers age, who is 10 years old, is 6
  years.
• y 10 6

• Sum means addition
• The sum of Pats age and 11 equals 28
• p 11 28

• Product means multiplication
• The product of Joes age and 14 is 162
• 14j 162

Slide 2
3
Essential Vocabulary

• Times means multiplication
• Three times Bens age is 45.
• 3b 45

• Less than means subtraction
• Seven less than my age equals 32.
• y 7 32

• Total means addition
• The total change under the couch cushion and 10
  dollars is 10.43
• c 10 10.43

• More than means addition
• Eleven more than the Principals age is 55.
• 11 p 55

Slide 3
4
Other Vocabulary words

• Variable A variable is a symbol that represents
  a number. Usually letters are used such as x, y,
  n, or t.
• Expression An expression is a mathematical
  statement that may use numbers, variables or
  both. An expression does not have an equal sign.
  Example x 2.
• Equation An equation is a mathematical statement
  that two numbers or expressions are equal. An
  equation always has an equal sign. Example x 2
  8
• Inequality A mathematical sentence that contains
  lt, gt, (insert a greater than or less than
  symbol), (insert a less than or greater than
  symbol), (insert a non equal symbol). Example x
  2 gt 8

Slide 4
5
Writing expressions from word sentences

• Examples of expressions
• 8
• X
• 3 4
• 2y 5
• 3 5(4-3)

• An expression is a mathematical statement that
  may use numbers, variables or both. An
  expression does not have an equal sign.

Slide 5
6
Writing expressions from word sentences

• Bart weighs 60 kilograms, and Maggie weights k
  kilograms. Write an expression for their
  combined weight.
• Four books more than b books
• The quotient of p and 8

Slide 6
7
Writing equations from word sentences.

• Examples of equations
• 3 3
• 18 15 3
• x 28
• t 4 9
• 4n 5 25

• An equation is a mathematical statement where
  two numbers or expressions are equal. Equations
  do have equal signs.

Slide 7
8
Writing equations from word sentences.

• Translate the following into an equation
• The sum of 8 and a number is
• equal to 30
• Thirty-seven more than a number is 8
• Eight fewer than a number is 10

Slide 8
9
Writing inequalities from word sentences.

• Examples of inequalities
• 3 ? 5
• 80 gt 15 3
• x lt 28
• 27 y
• t 9 1
•  

• An inequality is a mathematical statement that
  contains lt, gt, ,

Slide 9
10
Writing inequalities from word sentences.

• Translate the following into inequalities
• My favorite song is less than 5 minutes long.
• To drive a car you must be at least 14 years old.
• The truck can carry more than 650 pounds.

Slide 10
11
Writing expressions
Application 1
Write and solve this in your Journal.

• The cost of a candy bar divided among 3 friends.

• Translate into an expression

Slide 11
12
Writing equations
Application 2

• Write and solve this in your Journal.

• Suppose you have 32.00 to spend at Joyland.
  Admission cost 4.00. If ride tickets are 2.00
  per ticket, how many tickets can you buy?

• Translate the following word problem into an
  equation

Slide 12
13
Writing inequalities
Application 3
Write and solve this in your Journal.

• Translate the following word problem into an
  inequality

• My locker shelf can hold at most 50 pounds.

(Do not try this on your locker!)
Slide 13
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Demonstration
Step-by-Step 1
Who would like to write this on the board?

• Nine cards fewer than c cards

Slide 14
15
Demonstration
Step-by-Step 2
Who would like to write this one on the board?

• The sum of 45 and a number is 68

Slide 15
16
Demonstration
Step-by-Step 3
Who would like to write this on the board?

• The dogs age is over 10 years.

Slide 16
17
Show us what you can do!

• Write your own word problem. Then write the
  algebra problem that goes with this word problem
  and explain it to the class.
• You will need to be able to defend your answer if
  needed.

Slide 17
18
Do these on your own and we will check them
together.

• Write an expression, equation, or inequality for
  each word phrase.
• 1. Seven times your quiz score q.
• 2. The sum of 7 and a number is 40.
• 3. The temperature is over 100 F.

19
Quiz time

• Write an expression, equation, or inequality for
  each word phrase.
• Divide the total points p by 4
• Seventeen more than a number is 6
• To enter the movie, you must be 18 years old.
• 8 less than d dollars.

20

• 5. Seven fewer than a number is 12.
• You can walk there in 20 minutes or less.
• You plan to read 500 pages of a book in one week.
  You have read 142 pages so far this week. Set
  up an equation to find out how many more pages
  you must read?
• The sum of s students and 9 students.

21

• Twenty-seven is 4 less than a number.
• Each prize is worth over 1758.
• In a pet store the number of fish is 120 more
  than three times the number reptiles. The pet
  store has 210. Set up an equation to find out
  how many reptiles does it have?