Evaluating Expressions

Front

What is an expression in mathematics?

Back

An expression is a combination of numbers, variables, and operators (such as +, -, *, /) that represents a value.

Front

What does it mean to evaluate an expression?

Back

To evaluate an expression means to calculate its value by substituting the variables with given numbers and performing the operations.

Front

How do you substitute values into an expression?

Back

To substitute values, replace each variable in the expression with its corresponding numerical value and then simplify.

Front

What is the order of operations in mathematics?

Back

The order of operations is a set of rules that dictates the sequence in which calculations are performed: Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right), often abbreviated as PEMDAS.

Front

What is the value of the expression ½(10p - 7q) when p = 9 and q = 2?

Back

The value is 38.

Front

How do you evaluate the expression -7w² + 2w when w = -4?

Back

Substituting -4 for w gives -7(-4)² + 2(-4) = -7(16) - 8 = -112 - 8 = -120.

Front

What is the result of evaluating the expression 10c - cd + d³ for c = -6 and d = 2?

Back

The result is -40.

Front

How do you evaluate the expression (12xy)/(x - y) when x = 3 and y = -1?

Back

Substituting gives (12(3)(-1))/(3 - (-1)) = (-36)/(4) = -9.

Front

What is the value of the expression (18 - ab) + 4b when a = -2 and b = -5?

Back

The value is -12.

Front

What is a variable in an expression?

Back

A variable is a symbol (often a letter) that represents an unknown value in an expression or equation.