Expressions and Equations

a symbol or a letter

a number

$$\pi$$  

$$\infty\ or\ -\infty$$  

$$+,\ -,\ \times,\ \div$$  

$$\pi,\ \sigma,\ \phi$$  

a, b, c

x, y, z

Purple Elephants May Destroy a School

Parenthesis Exponents Multiplication Division Addition and Subtraction

People Eat More Donuts After School

Please Excuse My Dear Aunt Sally

an expression, rule, or law that defines a relationship between one variable and another variable

a combination of numbers, variables, functions

a value or number that never changes in expression.

a statement that the values of two mathematical expressions are equal

statement of equality between two expressions consisting of variables and/or numbers.

a relation between a set of inputs having one output each

a combination of numbers, variables, functions

a single mathematical expression

variables

$$=$$  

  $$\ge\ and\ \le$$  

numbers

expression

equation

expression

equation

x = 2

x = 5

x = 3

x = -5

x = -4

x = 2

x = 4

x = -2