expressions and variables

Numerial expression

a numerical expression consists of numbers and operations 3+5

Variable

a variable is a letter used to represent one or more numbers. x=6

variable expression

a variable expression consists of numbers, variables, and operations 7+3+4x

Evaluate a variable expression

to evaluate a variable expression, substitute a number for each variable and evaluate the resulting numerical expression

verbal model

a verbal model describes a problem using words as labels and using math symbols to relate the words

Associative property of addition

(3 +2) 4 = 3+ (2 +4)

Identity property of addition

0 + b = b

Identity property of multiplication

1(-7) = -7

commutative property of multiplication

cd=dc

Equivalent numerical expressions

numerical expressions that have the same value

equivalent variable expressions

equivalent variable expressions have the same value for all values of the variable(s)

Terms of an expression

The parts of an expression that are added together are called terms 4y, -6. 3y

Like terms

like terms are terms that have identical variable parts 4y and 3y

Coefficient of terms

The coefficient of a term with a variable is the number parts of the term 4, 3

Constant term

A constant term has a number but no variable -6

Equation

an equation is a mathematical sentence formed by placing an equal sign, = between two expressions x +3 = 7

Solution of an equation

a solution of an equation with a variable is a number that produces a true statement when it is substituted for the variable. x + 2 = 4 2+2 = 4

Solving an equation

finding all solutions of an equation is called solving the equation

Inverse operations

Inverse operations are two operations that undo each other, such as addition and subtraction

Equivalent equations

Equivalent equations are equations that have the same solutions(s)