🔢 Numbers or Variables
Is 7 a variable or a number?
Number
X+ 8= 20
What is the variable?
x
A classroom has s students.
What does s represent?
Number of students.
What operation is shown?
x + 12
Addition
Student says:
"In 7 + x, 7 is the variable."
What's wrong?
7 is a number. x is the variable.
Is x a variable or a number?
Variable
y − 6 = 14
What does y represent?
The unknown number that has 6 subtracted from it to equal 14.
A movie lasts m minutes.
What does m represent?
The number of minutes the movie lasts.
What operation is shown?
y − 9
Subtraction
Student says:
"The variable is always x."
True or false?
False.
Variables can be x, y, n, m, p, or other letters/symbols.
Identify the variables:5 +x=12
x
4n=28
what does n represent?
An unknown number that is multiplied by 4 to equal 28
A student has x dollars and spends 7 dollars.
What does x represent?
The amount of money the student had before spending $7.
What operation is represented by:
5n
Multiplication
Student says:
"In 4n + 8, n represents 8."
Is the student correct?
No.
n is the variable. 8 is a known number.
Which one is a variable?
A. 15
B. 8
C. n
D. 20
C. n
p/5=9
Identify:
-variable, operation, what it reprsents, and the values
p, division, the unknown nunber being divided by 5, and 45
A teacher has p pencils. She gives 4 pencils to each of 6 students.
Which expression represents the number of pencils given away?
4 × 6 = 24
Translate this situation into an expression:
A student has x dollars and earns $15 more.
x+15
A student sees:
x + 5 = 12
and says:
"x represents 12 because 12 is at the end."
Explain the mistake.
12 is a known number. x is the unknown variable.
Identify all the numbers AND variables:
3x + 7 = 22
Variables: x
Numbers: 3, 7, and 22
3x+5=20
A student says:
"x represents 5 because 5 is the number next to x."
Explain why the student is wrong.
5 is a known number in the equation. x is the variable and represents the unknown number.
A school has n students.
Each student receives 3 notebooks.
What does n represent?
What does 3 represent?
Write an expression for the total number of notebooks.
Translate the situation into an expression:
A teacher has p pencils and gives 3 pencils to each of 5 students.
How many pencils were given away?
3x5=15
A student says:
"The letter p always means pencils."
Is this statement correct?
No.
A variable's meaning depends on the situation.
For example:
p could represent pencils, points, people, pages, or something else.