Evaluating expressions with one variable

Front

What is an expression in mathematics?

Back

An expression is a combination of numbers, variables, and operators (like +, -, *, /) 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 variables with numbers and performing the operations.

Front

What is a variable?

Back

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

Front

What is the value of the expression 3x + 4 when x = 2?

Back

The value is 10, because 3(2) + 4 = 6 + 4 = 10.

Front

How do you evaluate the expression 5y - 3 when y = 5?

Back

Substituting y with 5 gives 5(5) - 3 = 25 - 3 = 22.

Front

What is the result of the expression 2a + 6 when a = 4?

Back

The result is 14, because 2(4) + 6 = 8 + 6 = 14.

Front

What does it mean to complete a table for a variable?

Back

Completing a table for a variable involves calculating the values of an expression for different values of that variable.

Front

If b = 4, what is the value of the expression 2b - 8?

Back

The value is 0, because 2(4) - 8 = 8 - 8 = 0.

Front

What is the expression for the perimeter of a rectangle with length l and width w?

Back

The expression is P = 2l + 2w.

Front

How do you find the area of a rectangle?

Back

The area A is found using the expression A = l * w, where l is the length and w is the width.