Evaluate Expressions

Front

What is the order of operations in mathematics?

Back

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

Front

What does it mean to evaluate an expression?

Back

To evaluate an expression means to calculate its value by substituting numbers for variables and performing the operations according to the order of operations.

Front

What is an algebraic expression?

Back

An algebraic expression is a mathematical phrase that can include numbers, variables, and operation symbols. For example, 3x + 5 is an algebraic expression.

Front

What is a variable in mathematics?

Back

A variable is a symbol, often a letter, that represents an unknown value in an expression or equation. For example, in the expression x + 2, x is the variable.

Front

How do you substitute a value into an expression?

Back

To substitute a value into an expression, replace the variable with the given number and then simplify the expression. For example, if r = 3 in 2r + 1, replace r with 3 to get 2(3) + 1.

Front

What is the result of evaluating the expression 3 + 4 x 6 - 4?

Back

The result is 19. First, perform multiplication: 4 x 6 = 24, then add and subtract: 3 + 24 - 4 = 23.

Front

Write an algebraic expression for '5 less than a number x'.

Back

x - 5.

Front

Evaluate the expression 2r + 1 if r = 3.

Back

The result is 7. Substitute r with 3: 2(3) + 1 = 6 + 1 = 7.

Front

Evaluate the expression 7a + 8b x 2 if a = 3 and b = 4.

Back

The result is 85. Substitute a and b: 7(3) + 8(4) x 2 = 21 + 32 x 2 = 21 + 64 = 85.

Front

Evaluate the expression 4b - 5a if a = 3 and b = 4.

Back

The result is 1. Substitute a and b: 4(4) - 5(3) = 16 - 15 = 1.