Download Algebraic Expressions and Equations

Algebraic Expressions
Intro to Algebra
Numerical Expression
A numerical expression represents one value
and can contain one or more numbers and
operations.
4 + 5 is a numerical expression. It represents
the value 9.
Example
Which numerical expressions represent a value
of 21?
a) 9 + 24
b) 4 + 7 + 14
c) 9 + 4 + 10
d) 7 x 3
e) 5 + 2 x 2 - 1
f) 160 ÷ 8
What if they are not numbers?
7+x
4y + 3
8–y÷2
Variables
A variable is a symbol that can represent
different values.
We can substitute numbers in for variables to
give the expression a value.
A Number next to a Variable
What does it mean when a number is written next
to a variable?
4x
it means to multiply.
4x means 4 times x.
Examples
1. In the expression x – 4, what is the value
when x = 10?
2. In the expression 5y + 2, what is the value
when y = -2?
3. In the expression
a = -56?
𝑎
7
, what is the value when
Evaluating more expressions
1. p + 11 – q (when q = 16, p = 32)
2. 1 ÷ x · y (when y = 4, x = 1)
3. 14 + b · c (when b = 2, c = 3)
Algebraic Expression
An algebraic expression contains variables,
numbers and operations. The value of an
algebraic expression can change.
Parts of an Algebraic Expression
• Terms – A term can be a constant, a variable,
or a number with a variable. Terms are
separated by either a + or a – sign.
• Coefficient – In a single term containing a
number and a variable, the number in front of
the variable is called the coefficient.
Creating Algebraic Expressions
Create an algebraic expression to represent the
following statements.
1. 5 more than a number.
2. 17 less than a number.
Remember…
Does order matter in addition
and/or subtraction?
Subtraction only
A word to be careful with…
Less than
Order is opposite
Create an Algebraic Expression
1. Andy had 14 pencils, but then he lost some.
2. Jake had a number of baseball cards, and
then he got 24 more.
3. Diane reduced the number of calories she
ate by 50.