Scientific notation is a method of writing very large or very small numbers in decimal form. The method is used by scientists, engineers, and mathematicians. Scientific notation is also called standard form, standard index form, or scientific form. Examples of large numbers written in scientific notation include Avogadro’s number (6.022 […]

# Mathematics

The number π or pi is a mathematical constant that is the ratio of a circle’s circumference to its diameter (π = C/d). The ratio is a constant no matter what size of circle is used. Pi is also called Archimedes’ constant. Although pi is often approximated as 3.14159, its […]

## Pi Facts

Positive and negative numbers are two broad classes of numbers that are used in math and also everyday transactions, like managing money or measuring weight. A positive number has a value greater than zero. Its sign is positive, but it is usually written without a plus sign in front of […]

## Rules for Positive and Negative Numbers

This is a math dictionary of common terms used in arithmetic, geometry, algebra, trigonometry, and statistics. It covers math concepts for kids in grade school through high school. Abacus: An early counting tool using sliding beads on wire or string used for basic arithmetic. Abscissa: x-coordinate in a Cartesian coordinate system or […]

## Math Dictionary for Kids

Have ever wondered how many zeros are in a million, billion, or trillion? Do you know how many zeros are in a vigintillion or a googol? Knowing how to write ordinary large numbers is useful for science or math class (or your bank account, if you are rich). Use your knowledge […]

## How Many Zeros in a Million, Billion, and Trillion?

Law of Cosines example problems showing how to derive the law and how to use it to find the lengths of the sides or angles of a triangle.