Read the expression
n + 30
What is a variable?
A lowercase letter that represents an unknown value
a number plus 7
n + 7
other lowercase letters as variables are acceptable
7 times 7
49
10 times 0
0
5 + 12 = x
five plus twelve equals (or is) x
Why do we use a variable?
To represent an unknown number
a number divided by 10
x/10
12 divided by 1.2
10
What is half of 12?
6
3(n)
Is this a variable expression or a variable equation?
h + 10
Variable expression
13 is the sum of a number and 10
x + 10 = 13
2(3+5)
16
Algebra is the type of math that has something _____________.
unknown
p = 4(1)
a number equals 4 times 1
Create a variable equation
Any answer with an = that has one variable is correct
15 minus a number is 4
15 - n = 4
12 times 11
121
An equation DOES have an equals bar. Expressions do not.
y + 14 - 13
a number plus fourteen minus 13
How many variables are there in this problem?
ck + 4
2: there are two unknown numbers
c and k
12 less than a number
n - 12
Now that x is a variable, what do we use to show multiplication?
A dot in the middle
What is Ms. O'Neill's favorite number?
13