**Algebraic expression -**An expression consisting of at least one variable and also consist of numbers and operations.

**Coefficient -**The number part of a term that includes a variable. For example, 3 is the coefficient of the term 3x.

**Constant -**A quantity having a fixed value that does not change or vary, such as a number. For example, 5 is the constant of x + 5.

**Equation -**A mathematical sentence formed by setting two expressions equal.

**Inequality -**A mathematical sentence formed by placing an inequality symbol between two expressions.

**Term -**A number, a variable, or a product and a number and a variable.

**Numerical expression -**An expression consisting of numbers and operations.

**Variable -**A symbol, usually a letter, which is used to represent one or more numbers.