A coefficient is a number that is multiplied by a variable.

• In the expression  , the coefficient of  is 3.
• In the expression  , the coefficient of  is 1, because  .

The word cubed means “to the third power.” This is because a cube with side length has a volume of , or .

Equivalent expressions are always equal to each other. If the expressions have variables, they are equal whenever the same value is used for the variable in each expression.

For example,   is equivalent to  .

• When  is 3, both expressions equal 21.
• When  is 10, both expressions equal 70.
• When is any other number, both expressions still have equal value.

In expressions like and , the numbers 3 and the 2 are called exponents. They tell how many times a number is used as a factor.

For example, = , and .

A solution to an equation is a number that can be used in place of the variable to make the equation true.

• The solution to the equation is 7, because it is true that .
• The solution to is not 9, because does not equal 8. 

The word squared means “to the second power.” This is because a square with side length has an area of , or .

A term is a part of an expression. It can be a single number, a variable, or a number and a variable that are multiplied together.

• 7, , and  are examples of terms.
• The expression has 2 terms: and .

A variable is a letter that represents a number. Different numbers can be chosen for the value of the variable.

In the expression  , the variable is .

• If the value of  is 3, then  , because  .
• If the value of  is 6, then  , because  .