Lesson 1.3 Variables & Expressions
(text pages 17-21)
Defn. Variable – a placeholder for any
value. (p. 17)
 The root word of variable is vary which
means likely to change.
Defn. Algebraic Expression – any
expression that contains sums and/or
products of variables and numbers. (p. 17)
Ex 1, 2x + y
ab
x–7
a
4
a
4
Even though the expression uses
division, it is still an algebraic expression
because it can be written as
means
1 a 1 a a
 

4 1 4 1 4
1
a
4
which
 You can evaluate an expression for
different values of a variable.
Ex 1. Evaluate the expression 7m (which
means 7 × m) when…
m
1
2
5
10
7m
Defn. Defining a variable- means
assigning a variable to the unknown value
(p. 18)
~ it is often called a “let” statement
Translate each phrase into an algebraic
expression.
35 more than the number of tickets sold
The difference of six times a number and
10
The sum of a number and six
Twice a number decreased by seven
Six less than a number squared
Three times the sum of a number and six
Eight more than the quotient of a number
and nine