Absolute Value

Two bars that drop around an expression and force everything to be sunshine and rainbows: real positive stuff.

Absolute Value Inequality

An inequality that includes absolute value bars on some of the expressions. It's actually a compound inequality in disguise.

Compound Inequality

Two inequalities joined by "and" or "or." Does not collect compound interest.

Equations

Two expressions connected by an equal sign.

Expressions

A collection of numbers and variables that represent some quantity. Mothers everywhere warn that, if you keep an expression for too long, your face will stick looking that way.

Inequality

A relation between two algebraic expressions that are not equal, expressed using symbols like <, >, ≤, ≥. However, those expressions are currently marching on Washington, and hopefully, someday soon, there will be equality for all.

Integer

The natural numbers (1, 2, 3, 4...), their negatives (...-4, -3, -2, -1), and 0. These are the numbers that are the easiest to work with. Some of those fractions and decimals have severe social disorders.

Irrational Number

A number that feels safer in a car than on an airplane, even though statistics clearly indicate that you're much more likely to be in an automobile accident than a plane crash. Also, it's a real number that cannot be expressed as a fraction of two integers p/q, where q ≠ 0. Irrational numbers do not have finite or repeating decimal representation. For example  π, e, and the square root of 2 are irrational numbers.

Rational Number

A real number that can be expressed in the form of a fraction of two integers p/q, where q ≠ 0. Remember, rational numbers put the "ratio" in "rational." And a ratio is nothing more than a fraction. It's just a cooler sounding word.

Real Number

A number contained within the set of rational and irrational numbers. Real numbers can be represented by all points on a number line. So pretty much any number whatsoever (except for those sneaky imaginary numbers) is a real number. Some of them used to be wooden numbers, but then they had their wishes granted by the Blue Fairy.