In English we use the word combination loosely, without thinking if the order of things is important. In other words:

Find out how many different ways to choose items. For an in-depth explanation of the formulas please visit Combinations and Permutations.

Combinations and Permutations. Combinations and Permutations Calculator.

Math explained in easy language, plus puzzles, games, quizzes, worksheets and a forum. For K-12 kids, teachers and parents.

Here are some really useful applications to speed your way to that all-important solution.

A Sequence is a set of things (usually numbers) that are in order. In a Geometric Sequence each term is found by multiplying the previous term...

A Linear Equation is an equation for a line. A linear equation is not always in the form y = 3.5 − 0.5x,. It can also be like y = 0.5(7 − x).

Just type, and your answer comes up live. Example: It is used like this: Sigma is fun to use, and can do many clever things.

A Complex Number. A Complex Number is a combination of a Real Number and an Imaginary Number. Real Numbers are numbers like:

Integration can be used to find areas, volumes, central points and many useful things. It is often used to find the area underneath the graph of...